Britannica Student Encyclopedia - 2010

the fall of 1838 U.S. troops began

rounding up about 15,000 Cherokee

and putting them in prison camps.

Local residents burned their homes.

Troops then sent the Cherokee west in

groups of about 1,000.

The Cherokee suffered terribly on the

march, which lasted 116 days. They had

to walk in the cold, and they were not

allowed to rest. They did not have

enough food. Some went by boat in

conditions that were just as bad. About

4,000 Cherokee died.

90 Trail of Tears BRITANNICA STUDENT ENCYCLOPEDIA

In Oklahoma the Cherokee were given

some land. Many Cherokee still live

there.

#More to explore

Cherokee • Jackson, Andrew • Native

Americans

Transplant

During the type of surgery called a

transplant, doctors remove a part from a

person’s body and then replace it with a

similar part. A transplant is also called a

graft. The purpose of a transplant is to

replace a damaged or sick body part

with a part that works.

The working part can be from the person’s

own body or from another person.

The person who gets the body part is

called the recipient. If another person

gives a body part, that person is called

the donor. Transplant donors can be

living or dead.

When a doctor moves a body part from

one place to another on the same person,

the operation is called an autograft.

One common type of autograft is a skin

graft. This operation uses skin from one

area of a person’s body to replace lost

skin on another area.

When a doctor transplants a body part

from another person into a recipient, the

operation is called an allograft.

Allografts can be done with many body

parts, including kidneys, livers, lungs,

and intestines. These parts can come

from living donors. Corneas (parts of

eyes needed for sight) and hearts must

come from dead donors. Doctors also

can replace certain diseased parts,

including heart valves and hip sockets,

with artificial, or man-made, ones.

The main problem with transplants is

rejection. When this happens the body’s

immune system treats the new part like

a germ or an infection and tries to kill it.

To prevent rejection doctors give recipients

medicines that keep the body from

attacking the new part.

#More to explore

Immune System • Surgery

Transportation

Transportation is a general word for all

the methods people use to move themselves

and their goods from one place to

another. Just as they have for thousands

of years, people today rely on walking to

travel short distances. For longer distances,

people depend on animals,

bicycles, automobiles, trucks, railroads,

ships, and airplanes.

Doctors can replace a damaged hip joint

with an artificial joint made out of metal

and plastic.

BRITANNICA STUDENT ENCYCLOPEDIA Transportation 91

Reasons for Transportation

The world’s economy depends on

transportation. Raw materials must be

moved from where they are produced

to factories, where they are processed.

Food, minerals, and wood often travel

by truck, railroad, or ship. Oil and gas

often travel by pipeline. Next,

manufactured products must be moved

from factories to stores. They may

travel by truck, railroad, ship, or

airplane.

People need transportation to get from

home to work, too. Many people drive

cars to work. Others take public transportation,

including buses and trains.

People also take cars, trains, ships, and

airplanes to get to vacation spots and to

visit family and friends. Some people

drive just for enjoyment.

History

Early Transportation

Walking was the main method of transportation

until humans domesticated, or

tamed, animals. Camels, horses, and

cattle then carried goods and people.

More than 5,000 years ago people

invented the wheel. This allowed animals

to pull carts. Ancient peoples also

traveled by water, at first with simple

dugout canoes and rafts.

The Persians built a system of roads in

the 500s BC. The ancient Egyptians,

Indians, and Chinese also built roads.

By the AD 200s the Romans had built

roads across Europe.

Transportation by water expanded in the

Middle Ages (AD 500–1500). New ships

were built with multiple sails. They were

able to travel farther and faster than

earlier ships that were powered by rowing.

Improvements in navigation made

it possible to sail farther from land. Voyages

of discovery in the 1400s and 1500s

opened up trade routes between distant

points.

Modern Transportation

The invention of the steam engine in

the 1700s was an important event in

transportation history. Steam-powered

boats could easily travel upriver. Steampowered

ships could cross oceans without

wind. On land, inventors used

steam engines to power locomotives.

This led to the growth of railroads. By

1869 a railroad ran across the United

States, and steamships regularly crossed

Some people transport themselves through

a city on foot. Others use trains or cars.

92 Transportation BRITANNICA STUDENT ENCYCLOPEDIA

the Atlantic Ocean. Trips that had taken

weeks now took days.

Builders of canals made some ocean

trips much shorter. The Suez Canal in

Egypt shortened the trip between

Europe and Asia by thousands of miles.

The Panama Canal in Panama shortened

the trip between the East andWest

coasts of North America.

The late 1800s saw the first successful

bicycles and automobiles. They made

quick and easy transportation available

to more people than ever before. People

who bought cars demanded more and

better roads.

In 1903 the U.S. inventorsWilbur and

OrvilleWright flew the world’s first

airplane. The invention of the jet engine

in the 1940s made air travel the fastest

transportation in history.

Transportation Problems

Advances in transportation have led to

problems, however. Cars and trucks

cause traffic jams, accidents, and air

pollution. These vehicles also use oil for

fuel. The supply of oil is limited and

controlled by a few countries. To ease

crowded roads, governments have

worked to improve public transportation.

To fight pollution, scientists are

developing vehicles that run on different

types of fuel.

#More to explore

Airplane • Automobile • Bicycle • Boat

• Canal • Navigation • Railroad • Road

• Ship

Tree

Trees are tall, woody plants. They usually

have a stem called a trunk. Trees are

the largest and oldest living things on

Earth. Some trees live for hundreds or

even thousands of years. There are more

than 80,000 species, or types, of tree.

Well-known trees include birches, firs,

maples, palms, and pines.

Groups of Trees

Scientists divide trees into groups based

on how they reproduce. Some trees

reproduce with spores, or particles that

grow into new plants. They are called tree

ferns.Most trees reproduce with seeds.

An ocean liner unloads war prisoners during

World War II (1939–45). Liners were

an important means of transportation during

the first half of the 1900s. In peacetime

they carried rich people to vacation spots

and poor immigrants to new homes.

BRITANNICA STUDENT ENCYCLOPEDIA Tree 93

Some seed-bearing trees grow their seeds

in cones. They are called conifers.Most

conifers have needle-shaped leaves.

Other seed-bearing trees grow their seeds

in fruits or pods. They are known as

broad-leaved or flowering trees. They

have broad, flat leaves.

Scientists also group trees based on

whether they lose their leaves. Trees that

keep their leaves year-round are called

evergreens. Trees that lose their leaves at

some point during the year are called

deciduous trees.

Physical Features

Trees are usually more than 10 feet (3

meters) tall. They have roots, a trunk,

branches, and leaves. The trunk and

branches are made of fibers called wood.

These fibers are protected by an outer

covering called bark. As the tree ages,

the trunk and branches thicken.

The Lawson cypress and the English elm look different because they are two different types

of tree. The Lawson cypress is a conifer and an evergreen. It produces seeds in cones and

has needlelike leaves that stay on all year. The English elm is broad-leaved and deciduous.

It produces seeds in fruits and has leaves that fall off in autumn.

People grow eucalyptus trees for their wood

and oil. The leaves of some kinds of eucalyptus

contain an oil used in medicines.

94 Tree BRITANNICA STUDENT ENCYCLOPEDIA

The leaves make food for the tree

through a process called photosynthesis.

Veins run through the leaves. They carry

water and food to and from the

branches. Leaves are usually green. The

leaves of deciduous trees often change

colors in autumn before they fall off.

New leaves then grow in spring.

Uses

Trees are very important to people. Tree

wood is used to build homes and furniture.

Paper is made from wood fibers.

Many people burn wood to cook and to

heat their homes. Farmers plant trees

that grow fruit for people to eat.

Trees also help keep the air clean. They

release oxygen for animals, including

humans, to breathe. They take in the

carbon dioxide that animals breathe out.

..More to explore

Bark • Birch • Conifer • Fir • Maple

• Palm • Photosynthesis • Pine • Plant

Trenton

Population

(2000 census)

85,403; (2007

estimate)

82,804

Trenton is the capital of the U.S. state of

New Jersey. In 1776, during the American

Revolution, American troops won

an important battle in the city.

Government is the largest employer in

Trenton by far. Many other people in

the city work in health care, trade, and

other service industries. Factories in

Trenton make medicines, metal products,

and pottery.

The first Europeans to settle in the area

that is now Trenton arrived in 1679. In

1714 a businessman namedWilliam

Trent established the town. It was later

named Trenton in his honor.

The battle of Trenton took place in

December 1776, during the American

The State House in Trenton is the meeting

place of the New Jersey General Assembly,

or state legislature.

BRITANNICA STUDENT ENCYCLOPEDIA Trenton 95

Revolution. General GeorgeWashington

led American troops across the Delaware

River. The next day they launched

a surprise attack on British troops in

Trenton. The Americans won the battle.

Trenton was the temporary capital of the

United States in 1784 and again in

1799. It became the capital of New Jersey

in 1790.

#More to explore

American Revolution • New Jersey

Triceratops

The dinosaur known as Triceratops

looked something like a modern rhinoceros.

However, it had three sharp horns

on its head. The name Triceratops means

“three-horned face.” Triceratops also had

a bony neck frill that surrounded the

head like a huge collar.

When and Where

Triceratops Lived

Triceratops lived about 70 to 65 million

years ago. It was among the last dinosaurs

to live on Earth before the dinosaurs

disappeared. Fossils, or remains, of

Triceratops have been found in North

America.

Physical Features

Triceratops was the largest of the horned

dinosaurs. It weighed up to 5 tons and

reached a length of nearly 30 feet (9

meters). The skull and neck frill of

Triceratops often measured more than 6

feet (2 meters) long. Each of the two

horns above the eyes was longer than 3

feet (1 meter). The horn on the snout

was short and thick. The massive body

of Triceratops was supported by four

sturdy legs. Its back legs were longer

than its front legs. It had feet like an

elephant. Triceratops had a fairly short,

thick tail.

Behavior

Triceratops was a slow-moving plant

eater. The neck frill acted as a protective

shield against such enemies as Tyrannosaurus

rex. Triceratops also used its long

horns to defend itself and to fight rival

males. Triceratops lived and traveled

together in groups. Adults may have

protected their young by forming an

outward-facing circle around them.

Triceratops

96 Triceratops BRITANNICA STUDENT ENCYCLOPEDIA

Trinidad and Tobago

The Republic of Trinidad and Tobago is

an island country in the Caribbean Sea.

The capital is Port of Spain.

The island of Trinidad is larger than the

island of Tobago. Trinidad is only about

7 miles (11 kilometers) from the coast of

Venezuela in South America. Both

islands are mountainous. Trinidad has

many short rivers, but Tobago has only a

few streams. The country has a warm

climate with dry and rainy seasons.

Tropical rain forests grow in the high

areas. The islands’ animals include

golden tree frogs, porcupines, armadillos,

wild pigs, and rodents. The scarlet

ibis is the country’s national bird.

Blacks and East Indians each make up

about 40 percent of the population.

Most of the rest of the people have

mixed roots. English is the main language.

More than half of the people are

Christians. Many of the East Indians

follow Hinduism or Islam.

Trinidad and Tobago has a strong

economy. The country produces petroleum

(oil) and natural gas. Manufacturing

and tourism are also important to

the islands. The country’s products

include sugar, chemicals, fertilizers, steel,

and cement. Farmers grow sugarcane,

oranges, rice, coffee, and cocoa.

Arawak Indians lived on Trinidad when

Christopher Columbus arrived in 1498.

As the Spanish took control, almost all

the Indians died. French settlers came in

the 1700s. They brought Africans with

them as slaves. Great Britain took over

Trinidad in 1797 and Tobago in 1814.

The British brought people from India

to work on plantations.

Trinidad and Tobago gained independence

in 1962. The country discovered

its huge oil and gas deposits in 1998.

..More to explore

Caribbean Sea • Port of Spain

Children dress in colorful costumes for a

carnival celebration in Trinidad and Tobago.

Facts About

TRINIDAD AND

TOBAGO

Population

(2008 estimate)

1,305,000

Area

1,980 sq mi

(5,128 sq km)

Capital

Port of Spain

Form of

government

Republic

Major cities

Chaguanas, San

Fernando, Port of

Spain, Arima,

Point Fortin

BRITANNICA STUDENT ENCYCLOPEDIA Trinidad and Tobago 97

Tripoli

Population

(2005

estimate), city,

911,643; urban

area,

2,098,000

Tripoli is the capital of Libya, a country

in northern Africa. The city lies on a

piece of rocky land overlooking the

Mediterranean Sea. It is Libya’s largest

city and main seaport.

Shipping oil and other goods through

the port brings money to Tripoli. The

city is also Libya’s main center of business

and industry.

In ancient times the city was called Oea.

People called the Phoenicians founded it

in the 600s BC. It was one of the three

main cities in the Phoenician region

called Tripolitania, which means “Three

Cities.” The city became part of the

Roman Empire and later the Byzantine

Empire.

Muslim Arabs conquered Tripoli and the

rest of Libya in about AD 645. The Turkish

Ottoman Empire ruled Libya from

1551 until 1911. Then Italy and, later,

Great Britain controlled Libya. In 1951

Libya became an independent country

with Tripoli as its capital.

..More to explore

Libya

Tropical Rain

Forest

..see Rain Forest.

Tropics

The region of Earth’s surface that is

closest to the equator is called the tropics.

Two imaginary lines that circle the

globe mark the boundaries of the tropics.

The line called the Tropic of Cancer

marks the northern edge. Its latitude

(distance from the equator) is 23° 27' N.

The line called the Tropic of Capricorn

marks the southern edge. Its latitude is

23° 27' S.

The tropics are the only part of Earth

where the sun sometimes shines straight

down. Because the sunlight is so strong,

the tropics are generally warmer than

other parts of Earth. Tropical temperatures

are warm or hot throughout the

year. The temperatures do not change

A child plays near the People’s Palace in

Tripoli, Libya. The building was the king’s

palace when Libya was a kingdom.

98 Tripoli BRITANNICA STUDENT ENCYCLOPEDIA

greatly, but winds and rain bring different

types of weather. Most tropical

places experience wet and dry seasons.

Areas closest to the equator are the wettest.

A great deal of rain falls year-round.

Dense rain forests cover the land. The

largest tropical rain forests on Earth lie

in Brazil and in parts of Africa.

The climate is drier in tropical regions

that lie farther north and south of the

equator. In these regions there are one or

two dry seasons each year. The forests

may be deciduous, meaning that the

trees shed their leaves during the dry

periods. Savannas, or grasslands with

scattered trees, are also common.

The driest parts of the tropics lie near the

northern and southern edges.Here the

dry season is long. Few trees grow. Shrubs

and low grasses cover the land.Two of

Earth’s big deserts, the Sahara and the

Kalahari, lie on the edges of the tropics.

Many plants and other products that

people value come from the tropics. Some

of these are bananas, coffee, cocoa, tea,

rubber, spices, nuts, and tropical wood.

#More to explore

Desert • Equator • Rain Forest

Trout

Trout are a kind of fish that many

people like to catch and eat. Trout are

closely related to salmon. Most species,

or types, of trout are freshwater fish.

Many live in clear, cool streams and

lakes. Some types live in the ocean but

return to freshwater to breed.

There are two main groups of trout species:

black-spotted trout and speckled

trout. The species of black-spotted trout

include rainbow, cutthroat, and golden

trout. Black-spotted trout range in color

from silver, brown, or dark gray to shiny

green, blue, red, or gold. They all have

small black spots on the back.

The species of speckled trout include

brook, Dolly Varden, lake, and bull

trout. Some speckled species are also

called chars. Speckled trout have lighter

spots on a darker body. Many speckled

species have pinkish or red spots, especially

on the underside.

The brown trout is separate from the

black-spotted trout and speckled trout.

It has a brown body with black spots.

The rainbow trout is popular with people

who fish for sport.

BRITANNICA STUDENT ENCYCLOPEDIA Trout 99

Trout vary in size, depending on the

species. Many species of trout are about

1 foot (30 centimeters) long.

Trout eat insects, small fish, and eggs of

other fish. Many species spawn, or

reproduce, in the spring or the fall. The

females bury their eggs in gravel nests

that they dig in the bottom of streams.

The eggs hatch after two or three

months.

#More to explore

Fish • Salmon

Truman,

Harry S.

After President Franklin D. Roosevelt

died in 1945, Vice President Harry S.

Truman became the 33rd president of

the United States. Truman led the country

through the end ofWorldWar II.

After the war he worked to stop the

spread of Communism.

Early Life and Career

Truman was born in Lamar, Missouri,

on May 8, 1884. He was the oldest of

the three children of John Anderson

Truman, a farmer, and Martha Young.

Harry graduated from high school in

Independence, Missouri.

A member of the Missouri National

Guard, Truman volunteered to serve in

WorldWar I in 1917. He fought in

France and then returned to the United

States in 1919. That year he married

Elizabeth (Bess)Wallace. They had one

daughter.

With an Army friend, Truman opened a

men’s clothing store in Kansas City. The

business failed in the early 1920s.

Political Career

The Democrats who controlled Kansas

City got Truman elected as a county

judge in 1922. In 1934 he won a seat in

the U.S. Senate.

In 1944 President Roosevelt chose Truman

as his vice presidential running

mate. After winning the election,

Roosevelt died suddenly on April 12,

1945. Truman then became president.

Presidency

WorldWar II in Europe soon ended,

but war with Japan continued. Hoping

to prevent more U.S. deaths by making

Harry S. Truman was the 33rd president of

the United States.

100 Truman, Harry S. BRITANNICA STUDENT ENCYCLOPEDIA

Japan surrender, Truman decided to use

the newly invented atomic bomb in

Japan. In early August 1945 U.S. airplanes

dropped atomic bombs on the

cities of Hiroshima and Nagasaki. The

bombs killed more than 100,000 men,

women, and children. Japan surrendered

on August 14, 1945.

After the war Truman helped the

United States join the United Nations,

a new international peace organization.

He also introduced the Truman

Doctrine. That policy said that the

United States would fight the spread of

Communism, the political system of

the Soviet Union.

In 1948 Truman approved the Marshall

Plan. Under the plan the United States

sent billions of dollars to help rebuild

Europe. By strengthening the economies

of western Europe, the plan prevented

Communism from spreading there.

That year Truman also ordered desegregation

(the mixing of races) in the U.S.

military.

After beginning his second term in

1949, Truman presented a program of

reforms called the Fair Deal. He wanted

more public housing, more money for

education, higher wages, governmentprotected

civil rights, and national

health insurance. Congress did not pass

most of the Fair Deal reforms, but citizens

debated Truman’s ideas for years to

come.

The KoreanWar began during Truman’s

second term. In 1950 Communist

North Korea invaded South Korea.

Backed by the United Nations, Truman

ordered U.S. military forces to help

South Korea. The war dragged on past

the end of Truman’s presidency.

Retirement and Death

After his term ended in 1953, Truman

retired to Independence, Missouri. He

May 8, April 12, August December 26,

1884 1944 1945 1945 1950 1953 1972

Truman is

born in Lamar,

Missouri.

Truman is

elected vice

president under

Franklin D.

Roosevelt.

Roosevelt dies;

Truman

becomes

president.

Truman orders

atomic bombs

dropped on

Japan; World

War II ends.

The Korean

War begins.

Truman retires

from office.

Truman dies in

Kansas City,

Missouri.

T I M E L I N E

BRITANNICA STUDENT ENCYCLOPEDIA Truman, Harry S. 101

died in Kansas City, Missouri, on

December 26, 1972.

#More to explore

Communism • KoreanWar • Roosevelt,

Franklin D. • United Nations • United

States •WorldWar II

Truth, Sojourner

Sojourner Truth spoke out against slavery

and for women’s rights in the

1800s. Her courage and powerful way of

speaking helped the causes of both African

Americans and women in the

United States.

Early Life

Truth was born a slave in the U.S. state

of New York in about 1797. She was

originally named Isabella Baumfree.

Isabella worked for several different

owners. Her last owner, Isaac VanWagener,

freed her just before slavery ended

in New York in 1827. Isabella took the

last name VanWagener.

Speaking Out

In 1829 Isabella moved to New York

City and worked as a house cleaner. In

1843 she left New York to become a

traveling preacher. She also changed her

name to Sojourner Truth.

Truth discovered that some people had

started working to end slavery. This

movement was called abolitionism. She

began speaking out against slavery in the

late 1840s. She soon became a popular

abolitionist speaker throughout the

North and the Midwest. In 1850 Truth

published her life story, called The Narrative

of Sojourner Truth.

Truth also defended women’s rights. She

complained that women could not vote

or serve on juries. She also pointed out

that they received less money than men

for the same work.

Later Years

After the American CivilWar started in

1861, Truth became even more famous.

In 1864 she visitedWashington, D.C.,

where she met President Abraham Lincoln.

Also in 1864 Truth took a job with

the National Freedmen’s Relief Association,

a group that helped former slaves.

In 1875 Truth retired to her home in

Battle Creek, Michigan. She died there

on November 26, 1883.

#More to explore

Abolitionist Movement • African

Sojourner Truth Americans •Women’s Rights

102 Truth, Sojourner BRITANNICA STUDENT ENCYCLOPEDIA

Tsar

When Russia had a royal family, the

emperor was called the tsar. A Russian

empress’s title was tsarina, a prince’s title

was tsarevich, and a princess’s title was

tsarevna. Tsars ruled Russia from 1547

to 1917.

The term tsar (also spelled czar) is the

Russian version of Caesar, the family

name of Julius Caesar and the first

emperors of Rome. The link between

Rome and Russia was the Byzantine

Empire, which began as the eastern

branch of the Roman Empire and fell in

1453. In 1472 Ivan III, the prince of

Moscow, married the niece of the last

Byzantine emperor. Ivan III’s grandson,

Ivan IV, was the first Russian ruler to

use the title of tsar. Known as Ivan the

Terrible, he had great power and ruled

harshly. Later tsars had similar qualities.

In 1721 Peter the Great stopped using

the title of tsar. Even so, Russia’s emperors

continued to be called tsars until the

last of them, Nicholas II, was removed

from the throne. Revolutionaries killed

Nicholas and his entire family in 1918

so that no descendants could claim the

title in the future.

#More to explore

Caesar, Julius • Ivan IV • Nicholas II

• Peter the Great • Russia

Tshwane

#see Pretoria.

Tsunami

Natural disasters, both on land and

under the ocean, may cause deadly

ocean waves called tsunamis. By the

time a tsunami reaches shore, it has

gained tremendous size and power. Tsunamis

can wipe out entire coastal villages

or towns.

Earthquakes, landslides, or volcanic

eruptions can trigger waves in a nearby

ocean. These waves may travel for thousands

of miles. They may move as fast as

500 miles (800 kilometers) an hour. As

they approach a coastline, the waves

move more slowly. They also rise, often

to heights as great as 100 feet (30

meters). As the first huge wave nears

Tsunami is a

Japanese

word.

Tsunamis used

to be called

tidal waves,

but they have

nothing to do

with tides.

Ivan IV, known as Ivan the Terrible,

was the first Russian ruler

to use the title of tsar.

BRITANNICA STUDENT ENCYCLOPEDIA Tsunami 103

land, the coastal water often draws back

dramatically. Then the tsunami hits the

land.

Tsunamis cannot be stopped, but there

are ways to defend against them. Scientists

around the world watch for early

signs of earthquakes. They also note

unusual changes in ocean levels.With

this information, scientists can warn

people to leave areas that a tsunami

might hit.

The Pacific Ocean is the site of many

tsunamis, but tsunamis can form in the

Atlantic and Indian oceans, too. A powerful

earthquake struck beneath the

Indian Ocean in December 2004. The

earthquake set off tsunamis that hit

about 10 countries. More than 200,000

people died.

#More to explore

Earthquake • Ocean

Tuberculosis

Tuberculosis, or TB, is a disease that

usually affects the lungs. Tuberculosis

used to be a leading cause of death in

Europe and North America. Today

tuberculosis is treatable.

Certain types of tiny living things called

bacteria cause tuberculosis. One type of

bacteria causes most cases of tuberculosis

in humans. It infects the lungs. This

may lead to coughing, chest pain, difficulty

breathing, loss of energy, and

weight loss. The person may even cough

up blood. Infected people spread the

disease to others when they cough or

sneeze.

Another type of bacteria causes a less

common form of tuberculosis. This

form of tuberculosis may damage the

bones and joints. Humans get it by

A doctor looks at the chest X-rays of

patients infected with tuberculosis.

A diagram shows the different elements of a tsunami. An undersea earthquake causes

waves to spread out in the ocean. As the waves approach a coast, they hit land under the

water. This makes the waves much larger.

104 Tuberculosis BRITANNICA STUDENT ENCYCLOPEDIA

drinking milk from a cow infected with

the bacteria. This form of tuberculosis

can be prevented by pasteurizing milk,

or heating it to kill the bacteria.

Tuberculosis spreads most easily in

crowded places where living conditions

are poor. In some countries people get

something called a vaccine to protect

them from tuberculosis. If people do get

tuberculosis, doctors treat them with a

medicine called an antibiotic. People

given antibiotics have a good chance of

recovering from the disease.

#More to explore

Bacteria • Disease, Human • Lung

Tubman, Harriet

In the middle of the 1800s Harriet Tubman

escaped from slavery in the southern

United States. She then helped lead

many other runaway slaves to freedom.

She also served the Union during the

American CivilWar.

Harriet Tubman was born in about

1820 in Dorchester County, Maryland.

She was one of 11 children of a slave

family. Her name at first was Araminta

Ross. She later changed her first name to

Harriet, which was her mother’s name.

In about 1844 Harriet married a free

African American named John Tubman.

In 1849, after hearing that she was to be

sold, she escaped to Philadelphia, Pennsylvania,

without her husband.

In Pennsylvania Tubman became a “conductor”

for the Underground Railroad.

The railroad was a secret network that

helped escaped slaves to find their way

to freedom. By 1857 she had freed hundreds

of slaves, including her own parents.

She said that she “never lost a

passenger,” even though slaveholders

offered large rewards for her capture.

During the American CivilWar, Tubman

went to South Carolina with the

Union Army. She served as a nurse and a

scout. She even led raids against the

Confederates.

After the CivilWar Tubman settled in

Auburn, New York, with her parents.

There she worked for racial justice and

also for women’s rights. She believed

that the two struggles were closely

linked. In 1908 she opened a home for

aged and poor African Americans. Harriet

Tubman died in Auburn on March

10, 1913.

#More to explore

African Americans • American CivilWar

• Slavery • Underground Railroad

Tubman was

called “the

Moses of her

people”

because she

led black

people to

freedom.

(Moses led

the Jewish

people to

freedom in

ancient times.)

Harriet Tubman

BRITANNICA STUDENT ENCYCLOPEDIA Tubman, Harriet 105

Tulip

Tulips are plants that bloom in early

spring. The flowers are cup-shaped and

very colorful. They are among the most

popular garden flowers. There are about

4,000 varieties of tulip. They belong to

the lily family.

Tulips first grew in south-central Asia.

People brought the flowers to Europe in

the 1500s and later to many different

parts of the world. The Netherlands

became the center of tulip production in

the 1600s. It still is today.

Tulips normally grow from bulbs that

are planted in autumn. Each bulb produces

a plant each spring for a few years.

A tulip plant has two or three thick,

bluish green leaves. These are attached at

the bottom of the stem. In most types of

tulip each stem grows a single flower.

Tulip flowers occur in almost every

color—white, yellow, pink, red, orange,

purple, and even brown and black. The

color is either solid or streaked. Streaked

tulips get their streaks because of a

harmless virus. The virus makes the top

color disappear in some places. The

flower’s underlying white or yellow color

then shows through.

#More to explore

Flower • Lily • Netherlands, The

Tuna

Tuna are large fish that live in most parts

of the world’s oceans. They belong to

the same family of fish as mackerel.

Tuna is one of the most popular foods

that comes from the sea. Most of the

tuna that fishers catch is canned.

There are seven different species, or

types, of tuna: bluefin, albacore, yellowfin,

bigeye, blackfin, longtail, and southern

bluefin. The skipjack tuna is related

to these species, but it belongs to a separate

group of fish.

A tuna has a long, rounded body. It is

usually dark on top and silvery underneath.

Some species have spots or

stripes.

Many species of tuna are about 35 inches

(90 centimeters) long. The bluefin tuna

is the largest species. It can grow as long

as 14 feet (4 meters) and weigh up to

1,800 pounds (800 kilograms).

Tuna travel in large groups called

schools. Some species travel long distances.

Tuna feed on other fish, includ-

Tulips surround the trunks of birch trees. ing herring, menhaden, and mackerel.

106 Tulip BRITANNICA STUDENT ENCYCLOPEDIA

Some species also eat small, spineless

animals such as squid. Some types of

tuna return to the waters where they

hatched to spawn, or produce eggs.

#More to explore

Fish

Tundra

Tundras are large, barren regions with

no trees. In fact, the word tundra comes

from the Finnish word tunturia, which

means “treeless plain.” Tundras lie

between the permanent ice of the far

north and the northern forests of North

America, Europe, and Asia. They cover

about 20 percent of Earth’s surface.

Features

Tundras may be flat, hilly, or mountainous.

Little plant life grows on the bare or

rocky ground. Tundras in coastal areas

tend to be foggy. Snow covers the

world’s tundras for more than six

months of the year.

Types of Tundras

Arctic tundras lie in northern Europe,

Russia, Alaska, Canada, and Greenland.

In these tundras the winter temperature

may be as low as .25° F (.32° C). The

summer temperature may rise only to

40° F (4° C). Because of these cold temperatures,

Arctic tundras have a permanent

layer of frozen soil, called

permafrost. Some permafrost reaches as

deep as 1,500 feet (456 meters).

Alpine tundras lie farther south than

Arctic tundras. Alpine tundras are found

in high mountains above the tree line.

(The tree line is the highest place where

trees can grow.) They have short, cool

summers and less extreme winters than

Arctic tundras. Alpine tundras do not

have a layer of permafrost.

Life in a Tundra

Only low-growing plants, such as

mosses and shrubs, can survive in tundras.

Plantlike living things called

lichens also grow there.

Tundra animals must be able to survive

long, cold winters. Many birds live there

in the summer, but few stay through the

winter. Some common tundra animals

The bluefin tuna is the largest type of tuna.

Reindeer graze on the Arctic tundra of

Canada’s Northwest Territories.

BRITANNICA STUDENT ENCYCLOPEDIA Tundra 107

are reindeer, Arctic foxes, snowy owls,

musk oxen, and polar bears.

Very few people live in tundras. Arctic

peoples, including the Eskimo (Inuit),

tend to live in places where hunting and

fishing can provide enough food yearround.

Resources

The ground of many tundras contains

coal, oil, iron ore, lead, or other

resources. Many companies have set up

mining operations in tundra regions.

However, some people worry that mining

and oil drilling endangers tundra

plants and animals.

..More to explore

Eskimo • Lichen • Mining

Tunis

Population

(2007 estimate)

745,000

Tunis is the capital of Tunisia, a country

in northern Africa. It is the largest city

in Tunisia by far. Tunis lies near the

coast of the Mediterranean Sea. A canal

links it to a port on the sea.

Tunis is Tunisia’s center of industry.

Factories in the city make food products,

cloth, clothing, and electronics. Many

people in Tunis work in banking, tourism,

or other service industries.

People called the Libyans founded

Tunis in ancient times. Later, people

called the Phoenicians built the city of

Carthage nearby. Carthage became a

great power. Tunis came under its rule.

The Romans destroyed Tunis during a

war with Carthage in 146 BC. They

later rebuilt Tunis as a city of the

Roman Empire.

Arabs capturedTunis in the AD 600s. The

city later became the capital of aMuslim

empire. In the 1200sTunis was one of

the leading cities in theMuslim world.

Tunis and the rest of Tunisia became part

of theTurkishOttoman Empire in 1574.

France took control ofTunisia in 1881.

In 1956Tunisia became an independent

country withTunis as its capital.

..More to explore

Carthage • Tunisia

The Grand Mosque of Tunis, Tunisia, is

decorated with colorful tiles.

108 Tunis BRITANNICA STUDENT ENCYCLOPEDIA

Tunisia

Tunisia is the smallest country in North

Africa. In ancient times Tunisia was the

site of the great city of Carthage. Today

Tunisia’s capital is Tunis.

Geography

Tunisia shares borders with Algeria and

Libya. The Mediterranean Sea lies to the

east and the north. Tunisia is only about

100 miles (160 kilometers) from Sicily,

an island of Italy.

Mountain chains run through northern

Tunisia. The country’s largest river, the

Majardah, flows through the north. The

central part of Tunisia is a large plateau,

or area of flat, raised land. There are

shallow salt lakes farther south. The

southern tip of Tunisia is a part of the

Sahara Desert. The land there is sandy

and rocky.

Northern Tunisia has mild, rainy winters

and hot, dry summers. The south is

warmer and drier.

Plants and Animals

Most of Tunisia’s plants and animals are

in the cooler northern region. The north

has vineyards and forests of cork oak and

evergreen oak. Thorny bushes and

grasses grow farther south. The Sahara

region in the far south has few plants.

Tunisia’s animals include hyenas, wild

boars, jackals, gazelles, and cobras. Scorpions

live throughout the country.

People

Most of Tunisia’s people have a mixture

of Arab and Berber roots. (The Berbers

were the first people in the region.)

Most Tunisians call themselves Arabs.

The main language is Arabic, but many

people also speak French. Almost all the

people are Muslims. More than half of

all Tunisians live in cities and towns.

Most people live near the Mediterranean

coast.

Economy

Tourism and other services are key parts

of Tunisia’s economy. Manufacturing

and mining are also important. The

country’s factories make processed

foods, steel, chemicals, clothing, and

leather goods. Tunisia also produces oil.

Mines provide phosphates and iron.

Tunisia uses the phosphates to make

chemicals and fertilizers.

BRITANNICA STUDENT ENCYCLOPEDIA Tunisia 109

Many Tunisians work in agriculture.

Wheat and barley are the main food

crops. Farmers also grow olives, tomatoes,

sugar beets, citrus fruits, and dates.

Sheep, goats, and cattle are the main

livestock.

History

In ancient timesTunisia was a colony of

the Phoenicians, a people from what is

now Lebanon. In the 800s BC the

Phoenicians founded the city of Carthage

near what is nowTunis. By the 400s BC

the city controlled trade in the western

Mediterranean Sea. In the 200s and 100s

BC Carthage fought Rome in a series of

wars. The Romans destroyed Carthage in

146 BC and took over the land.

Muslim Arabs invaded the region in the

AD 600s. Spain and the Ottoman Turks

battled for control of the area in the

1500s. In 1574 the Turks defeated the

Spanish and made Tunisia a part of the

Ottoman Empire. As the Ottomans

weakened in the late 1800s, France,

Great Britain, and Italy tried to control

the region. Tunisia became a territory of

France in 1881. France allowed

Tunisia’s bey, or king, to stay on the

throne, but the French held the real

power.

Tunisia gained independence from

France in 1956. The next year Tunisia

ended its monarchy. The country’s first

president stayed in power until 1987.

Tunisia’s second president held power

into the 21st century.

..More to explore

Carthage • Tunis

Tunisia is home to many ancient buildings, including Islamic buildings called ribats. Ribats

served as both monasteries and fortresses.

Facts About

TUNISIA

Population

(2008 estimate)

10,325,000

Area

63,170 sq mi

(163,610 sq km)

Capital

Tunis

Form of

government

Republic

Major cities

Tunis, Safaqis,

Al-Arianah,

Ettadhamen,

Susah

110 Tunisia BRITANNICA STUDENT ENCYCLOPEDIA

Turkey

The Republic of Turkey lies partly in

Asia and partly in Europe. For centuries

Turkey was the heart of two great

empires—the Christian Byzantine

Empire and the Islamic Ottoman

Empire. Modern Turkey’s capital is

Ankara.

Geography

Most of Turkey is on a peninsula in

southwestern Asia. A peninsula is a piece

of land surrounded by water on three

sides. The peninsula is known as Anatolia

or Asia Minor. A small part of Turkey

is in southeastern Europe. Narrow

waterways and the Sea of Marmara separate

the two parts of Turkey.

The Black Sea lies north of Turkey.

Georgia, Armenia, and Iran are to the

east. Iraq, Syria, and the Mediterranean

Sea lie to the south. The Aegean Sea,

Greece, and Bulgaria lie to the west.

The Asian part of Turkey has

mountains and a central plateau, or

raised flat area. The highest peak is

Mount Ararat, which rises 16,853 feet

(5,137 meters). The European part of

Turkey is lower and flatter. The

country’s longest river, the Kizil, flows

through the peninsula.

Most of Turkey has a dry climate with

hot summers.Winters are cold in central

Turkey and mild near the coasts. Earthquakes

are common.

Plants and Animals

Grasslands cover much of the country.

Pine, oak, cedar, juniper, and chestnut

trees grow along the coast.

Deer, wild goats, bears, and lynx live

near the Mediterranean coast. Gazelles

and hyenas live in central and eastern

Turkey.Wolves, jackals, badgers, and

otters live throughout the country. Turkey’s

birds include buzzards, storks, vultures,

and eagles.

Parts of Turkey are very mountainous.

BRITANNICA STUDENT ENCYCLOPEDIA Turkey 111

People

Most of Turkey’s people are Turks. They

speak a language called Turkish. Most of

the rest of the people are Kurds. They

live in eastern Turkey and have their

own language. Almost all the people of

Turkey follow Islam.

More than half of the population lives in

cities and towns. Turkey’s largest city is

Istanbul.

Economy

Services and manufacturing are the main

parts of Turkey’s economy. Services

include communications, transportation,

and tourism. Manufacturers produce

fabrics, clothing, processed foods,

iron and steel, chemicals, cars, and electronics.

Turkey’s land provides oil, coal,

copper, and other minerals.

Many Turks are farmers. Wheat, sugar

beets, citrus fruits, cotton, olives,

tobacco, and figs are important crops.

Sheep, cattle, and goats are the main

livestock.

History

Humans have lived in the Asian part of

Turkey, called Anatolia, since at least

7000 BC. The Hittite people invaded in

about 2000 BC. Greeks and Persians later

fought over the land. Romans took over

Anatolia by about 30 BC.

Byzantine Empire

Under the Roman Empire, Anatolia

was at peace. In AD 395 the Roman

Empire was divided into western and

eastern parts. The eastern part became

known as the Byzantine Empire. Its

capital was the city of Constantinople

(now called Istanbul). Christianity was

the main religion of the Byzantine

Empire.

The Seljuk Turks invaded Anatolia

beginning in the 1040s. The Seljuk

Turks were Muslims from central Asia.

In 1071 they defeated the Byzantine

army. During the next 200 years the

Christians of Europe fought the Turks in

a series of wars known as the Crusades.

Ottoman Empire

In the late 1200s a new group of Turks

gained power in Anatolia. They founded

the great Ottoman Empire. In 1453 the

Ottoman Turks captured Constantinople.

They renamed the city Istanbul and

made it their capital.

The Hagia Sophia in Istanbul, Turkey, has

been a Christian church and a Muslim

mosque. Now it is a museum.

112 Turkey BRITANNICA STUDENT ENCYCLOPEDIA

By the mid-1500s the Ottoman Empire

stretched across North Africa, the

Middle East, and southeastern Europe.

The empire then grew weaker. It collapsed

at the end ofWorldWar I in

1918.

Turkey Under Ataturk

After the war many Turks were angry at

the Ottoman government, which had

lost much of the empire’s land. A military

leader named Mustafa Kemal

formed a separate government. In 1923

he founded the new country of Turkey.

The city of Ankara became the new

capital. Kemal became Turkey’s first

president.

Kemal ruled with strong powers. He

soon took the name Ataturk, which is

Turkish for “father of the Turks.”

Ataturk wanted to make Turkey a more

modern country. He closed Islamic

schools and courts. He banned traditional

clothes such as the fez, a type of

Turkish hat. He also gave women the

right to vote. Ataturk died in 1938.

Turkey After Ataturk

In 1960 and 1980 the military took over

Turkey’s government. In 1997 the military

forced the prime minister to step

down. Each time Turkey returned to

democracy.

Beginning in the 1950s Turkey disagreed

with Greece over control of the island of

Cyprus. Turkish forces invaded northern

Cyprus in 1974. Turkey supported the

Turks of Cyprus when they formed a

separate country in 1983.

Modern Turkey has also faced a long

rebellion by Kurds in the east. The

Kurds fought the Turkish government

from the 1980s into the 21st century.

..More to explore

Ankara • Byzantine Empire • Cyprus

• Islam • Istanbul • Kurd • Ottoman

Empire

about

2000 BC about 30 BC AD 395 1071 1300 1923 1983

Hittites invade

Anatolia.

Romans take

control of

Anatolia.

Anatolia

becomes part

of the

Byzantine

Empire.

The Seljuk Turks

defeat the

Byzantines.

The Ottoman

Turks gain

power.

The Republic of

Turkey is

formed.

Kurds begin

fighting the

Turkish

government.

T I M E L I N E

Facts About

TURKEY

Population

(2008 estimate)

71,002,000

Area

299,158 sq mi

(744,815 sq km)

Capital

Ankara

Form of

government

Republic

Major cities

Istanbul, Ankara,

Izmir, Bursa,

Adana

BRITANNICA STUDENT ENCYCLOPEDIA Turkey 113

Turkey

Turkeys are large birds. They are found

in the wild and they are also raised for

food. The two species, or types, of turkey

are the common turkey and the

ocellated turkey.

The common turkey prefers places with

mild temperatures. It usually has black

feathers mixed with a shiny green or

bronze color. The head and neck are

featherless, bumpy, and bright red.

Males have a piece of red skin growing

from the forehead. Male turkeys often

make a gobbling sound while females

make a clicking noise.

Some common turkeys live in the wild.

They are found in parts of Mexico and

the United States.Wild turkeys prefer

forests and swamps. Males weigh about

22 pounds (10 kilograms), but females

are much smaller.Wild turkeys can fly,

but only for short distances.

Many common turkeys are kept on

farms and raised for food. These turkeys

are usually heavier, and they cannot fly.

Their feathers are usually white.

The ocellated turkey is found in Central

America. It is much smaller than the

common turkey. It has a blue head and

neck with reddish yellow bumps. Its tail

feathers are tipped with blue and gold,

somewhat like a peacock. The ocellated

turkey is not raised for food.

Two male common turkeys in the wild display

their feathers.

(Left) Many turkeys are raised for their meat; (right) ocellated turkeys live only in the wild.

114 Turkey BRITANNICA STUDENT ENCYCLOPEDIA

Turkmenistan

Turkmenistan is a desert country in central

Asia. The capital is Ashgabat.

Turkmenistan is on the southeastern

coast of the Caspian Sea. It shares borders

with Kazakhstan, Uzbekistan,

Afghanistan, and Iran.

The sandy Karakum Desert covers most

of the land. Southern Turkmenistan has

some mountains and hills. Turkmenistan

has a very dry climate with hot summers

and cold winters.

Grasses and shrubs grow in the dry

areas. Fig and nut trees grow near the

mountains. Foxes, wildcats, cobras, lizards,

and gazelles live in the desert.

Leopards and porcupines live in the

hills.

Turkmenistan is named after its main

group of people, the Turkmen. The

country also has some Uzbeks, Russians,

and Kazakhs. Most of the Turkmen are

Muslims. The people live mainly in

southern oases (desert areas with a water

supply) and along the rivers in the east.

The economy of Turkmenistan depends

on agriculture and the production of

natural gas and oil. Farming is possible

with the help of irrigation, or artificial

watering systems. The main crops are

cotton and grain. People also raise sheep

and use their wool to make carpets. Factories

produce metals, machinery,

chemicals, and fabrics.

The Parthian Empire of Iran ruled the

region in ancient times. Turkmen

nomads, or wanderers, entered the area

by AD 1100. Russia conquered the

region by 1881. In 1925 Turkmenistan

became part of the Soviet Union. Turkmenistan

gained independence in 1991.

..More to explore

Ashgabat

A vendor sells dried fruits and nuts at a

market in Turkmenistan.

Facts About

TURKMENISTAN

Population

(2008 estimate)

5,180,000

Area

188,500 sq mi

(488,100 sq km)

Capital

Ashgabat

Form of

government

Republic

Major cities

Ashgabat, Turkmenabat,

Dashhowuz,

Mary,

Balkanabat

BRITANNICA STUDENT ENCYCLOPEDIA Turkmenistan 115

Turner, Nat

In the United States before the American

CivilWar, many slaves escaped to

freedom. Others rebelled with violence

against their owners. A slave named Nat

Turner led one of the bloodiest slave

revolts in U.S. history. Southern states

reacted to Turner’s revolt by passing laws

that made the lives of slaves even more

difficult.

Early Life

Nat Turner was born on October 2,

1800, on a farm in Virginia. He had

several owners. In 1831 he joined the

household of a man named Travis.

Unlike most slaves, Turner learned to

read and write. He also learned about

the Christian religion. He came to

believe that God had chosen him to free

all slaves.

Revolt

On August 21, 1831, Turner and seven

other slaves killed everyone in the Travis

family. In the next two days, Turner

picked up about 75 followers. They

killed about 60 white people.

Then about 3,000 whites rose up to stop

the revolt. Whites killed most of Turner’s

men. Whites captured Turner, put

him on trial, and put him to death on

November 11, 1831.

Turner’s revolt frightened Southern

whites. They blamed his rebellious spirit

on his education, so they tried to stop

slaves from learning to read and write.

They also tried to stop slaves from gathering

in groups.

#More to explore

Slavery

Turtle

A turtle is a reptile that has a shell covering

its body. Turtles are known for moving

very slowly. There are about 250

species, or types, of turtle.

Turtles are found in most parts of the

world. Most live in freshwater ponds,

lakes, or rivers. Others live in the ocean

or on land. Some turtles live in forests or

even in the desert. Land turtles are often

called tortoises. Some water turtles are

known as terrapins.

An account of Nat Turner’s slave

rebellion was published in 1832.

116 Turner, Nat BRITANNICA STUDENT ENCYCLOPEDIA

Turtles are all different sizes. The smallest

turtles are less than 4 inches (10 centimeters)

long. In contrast, the Atlantic

leatherback turtle can be more than 7

feet (2 meters) long. It can weigh more

than 1,500 pounds (680 kilograms).

Turtles have sturdy legs with short feet

and claws on the toes. Sea turtles have

flippers instead of front feet. A turtle’s

shell is made of bone. It is usually very

hard and strong. Most turtles can tuck

the head, legs, and tail inside the shell

for protection from enemies. Snapping

turtles cannot do this, but they have a

powerful bite for protection.

Turtles eat worms, snails, insects, jellyfish,

and shellfish. Many tortoises eat

only plants. Turtles can store food in the

form of fat. Some turtles can store water,

too. They can live for days or even weeks

without having anything to eat or drink.

All turtles lay their eggs on land. The

female digs a hole and lays her eggs in it.

The temperature in the nest usually

affects the sex of the baby turtles.

Warmer temperatures generally produce

females, while cooler temperatures produce

males.

Turtles live longer than most other animals.

Some species can live more than

100 years.

#More to explore

Reptile

Tuscarora

The Tuscarora are Native Americans of

New York State and Ontario, Canada.

In the 1700s they became the sixth tribe

to join the group called the Iroquois

Confederacy.

The Tuscarora lived in round homes

made from poles covered with bark.

Later they also lived in homes called

longhouses, which were large enough for

A desert tortoise creeps among wildflowers

in the U.S. state of California.

A Tuscarora dancer performs at the New

York State Fair in Geddes, New York.

BRITANNICA STUDENT ENCYCLOPEDIA Tuscarora 117

several families. The Tuscarora grew

corn, gourds, beans, and apples. They

also hunted and gathered wild plants.

By the early 1700s British colonists had

moved into Tuscarora territory. At that

time the Tuscarora lived in North Carolina

and Virginia. The settlers mistreated

the tribe. They kidnapped Tuscarora

men, women, and children and sold

them as slaves. They also took the tribe’s

lands without payment.

The Tuscarora fought back in 1711 by

attacking several British settlements. The

attacks started a war. At least 1,000 Tuscarora

were killed in the fighting. The

Tuscarora who survived fled north to

New York. There, in 1722, they joined

the Iroquois Confederacy.

After the American Revolution (1775–

83) many Tuscarora moved to new lands

near Lewiston, New York. That area

later became the Tuscarora Reservation.

Some Tuscarora moved to lands along

the Grand River in what is now Ontario.

That area is now the Six Nations

Reserve. At the end of the 20th century

nearly 2,500 Tuscarora lived in the

United States. More than 1,900 others

lived in Canada.

#More to explore

Iroquois • Native Americans

Tuskegee Airmen

The Tuskegee Airmen were the first

group of African Americans to fly warplanes

for the U.S. military. They served

duringWorldWar II. At that time, during

the 1940s, African Americans had

fewer rights than whites had. The Tuskegee

Airmen did their jobs as well as any

white pilots. After seeing how well the

airmen did, other African Americans

pushed harder for equal rights.

Before the United States enteredWorld

War II, the National Association for the

Advancement of Colored People

(NAACP) asked the U.S. government to

allow African Americans to fly warplanes.

The military was then segregated,

or separated by race. Because of

this, the U.S. Army started a training

program for African Americans only.

The airmen got their training in Alabama

at the Tuskegee Army Air Field

and at an African American college

called Tuskegee Institute. The first

Tuskegee Airmen graduated in 1942.

Eventually 992 pilots graduated from

the training program.

Most of the

Tuscarora

were on the

side of the

colonists during

the

American

Revolution.

A poster from World War II

shows an African American

airman.

118 Tuskegee Airmen BRITANNICA STUDENT ENCYCLOPEDIA

The Tuskegee Airmen served in Europe

and North Africa. They flew small airplanes

that protected bigger airplanes

that dropped bombs on enemy targets.

The airmen never allowed an enemy

airplane to shoot down a U.S. bomber.

In 1948, three years afterWorldWar II

ended, President Harry S. Truman

ended racial segregation in the military.

After that African Americans served

alongside whites.

#More to explore

African Americans • National

Association for the Advancement of

Colored People •WorldWar II

Tutankhamen

Tutankhamen was a pharaoh, or king, of

ancient Egypt in the 1300s BC. He

became pharaoh when he was still a

child. He is famous today because of the

many treasures found inside his tomb,

or grave.

Life

Tutankhamen married while very young.

His wife was the daughter of another

pharaoh named Akhenaton. Akhenaton

had tried to change the religion of

ancient Egypt. He wanted Egyptians to

have one god only, instead of many

gods. Tutankhamen brought back the

old religion with its many gods. He died

at about age 18.

Tomb and Treasures

Workers dug Tutankhamen’s tomb into

a hillside in southern Egypt. The place is

called the Valley of the Kings. (By Tutankhamen’s

time, Egyptians had

stopped burying pharaohs in pyramids.)

Thousands of years ago, robbers broke

into the tombs of other pharaohs in the

Valley of the Kings. They stole many

treasures from the tombs. The robbers

missed Tutankhamen’s tomb because

rubble from another tomb covered up

the entrance.

In 1922 Howard Carter, a British

archaeologist, found Tutankhamen’s

tomb and opened it. (An archaeologist is

a scientist who studies things that people

made in the past.) Carter found Tutankhamen’s

mummy, or preserved body,

within a nest of three coffins. The inner

coffin was solid gold. A gold mask with

the face of the pharaoh covered the

mummy’s head. The tomb also con-

Tutankhamen’s tomb was opened in 1922.

One of the most spectacular objects in the

tomb was a gold mask. It covered the head

of the king’s mummy.

BRITANNICA STUDENT ENCYCLOPEDIA Tutankhamen 119

tained furniture, statues, clothes, a

chariot, weapons, staffs, and various

other objects. The government of Egypt

now owns these treasures.

#More to explore

Egypt, Ancient • Mummy • Pharaoh

Tutu, Desmond

Desmond Tutu is a religious leader in

South Africa. His protests helped to

bring an end to South Africa’s apartheid

laws. Apartheid was a system that kept

blacks separate from whites. In 1984

Tutu received the Nobel peace prize for

his work.

Early Life

Desmond Mpilo Tutu was born on

October 7, 1931, in Klerksdorp, South

Africa. His father was a schoolteacher.

Tutu graduated from the University of

South Africa in 1954.

Tutu taught school for three years. Then

he went back to college to study religion.

In 1961 he became a priest in the

Anglican church. He then taught religion

in South Africa and Lesotho

(another country in southern Africa).

Career

Between 1972 and 1975 Tutu worked in

Great Britain for a Christian group

called theWorld Council of Churches.

Then he returned to Africa to serve the

Anglican church.

Between 1978 and 1985 Tutu led the

South African Council of Churches.

During this time he frequently made

nonviolent protests against apartheid

laws. The apartheid system made life

hard for blacks. They did not have the

same rights as whites.

In 1986 Tutu became archbishop of

Cape Town, South Africa. This made

him the leader of South Africa’s 1.6-

million-member Anglican church. He

was the first black to hold this job. In

1988 Tutu also became chancellor

(president) of the University of the

Western Cape in Bellville, South Africa.

He continued to protest against apartheid.

Apartheid finally ended in the early

1990s. In 1995 Tutu led a committee

that investigated the crimes of apartheid.

He retired as archbishop in 1996, but he

continued to teach.

#More to explore

Desmond Tutu Apartheid • South Africa

120 Tutu, Desmond BRITANNICA STUDENT ENCYCLOPEDIA

Tuvalu

The country of Tuvalu is made up of

nine small island groups in the Pacific

Ocean. Tuvalu’s capital is Vaiaku, on the

island group called Funafuti Atoll.

Geography

Tuvalu is in Polynesia, a part of the large

region called Oceania. Tuvalu’s islands

are made of coral. Five of the island

groups are atolls. Atolls are groups of

islets (small islands) that surround a

pool of water. Most of Tuvalu’s land is

only about 15 feet (4.5 meters) above

sea level. There are no rivers. Tuvalu’s

climate is hot and rainy.

Plants and Animals

Coconut palms, screw pines, ferns, and

grasses grow on the islands.Wildlife

includes Polynesian rats, lizards, and

turtles. Octopuses, crustaceans, and

many fish live in Tuvalu’s waters.

People

Almost all the people are Polynesians.

Most people speak a language called

Tuvaluan. English is also common. Most

people are Christians. Nearly half of the

population lives on Funafuti Atoll.

Economy

Most people work in agriculture and

fishing. Crops include coconuts, tropical

fruit, and sweet potatoes. Many people

leave the country to find work. Tuvalu’s

government sells its stamps to stamp

collectors around the world. Tuvalu also

sells the use of its Internet name, “.tv.”

History

The first settlers in Tuvalu came from

the islands of Samoa in about the AD

1300s. In 1892 Great Britain took over

Tuvalu, which was then called the Ellice

Islands. In 1916 Britain joined the Ellice

Islands with the Gilbert Islands (now the

country of Kiribati). The Ellice Islands

gained independence as Tuvalu in 1978.

..More to explore

Coral • Funafuti Atoll • Oceania

A traditional hut sits among palm trees on

Funafuti Atoll in Tuvalu.

Facts About

TUVALU

Population

(2008 estimate)

9,600

Area

10 sq mi (26 sq

km)

Capital

Vaiaku, on

Funafuti Atoll

Form of

government

Constitutional

monarchy

Major town

Fongafale islet

BRITANNICA STUDENT ENCYCLOPEDIA Tuvalu 121

Twain, Mark

The U.S. author Mark Twain wrote stories

of youthful adventures. His stories

are treasured by readers around the

world. He created Tom Sawyer, Huck

Finn, and other memorable characters.

Twain’s real name was Samuel Langhorne

Clemens. Mark Twain was the

name he used as a writer. He was born

on November 30, 1835, in the small

town of Florida, Missouri. When he was

4 years old he moved with his family to

Hannibal, Missouri, on the Mississippi

River.

In 1847 Samuel’s father died. From then

on Samuel had to help support the family.

At age 13 he started working with a

local printer. Later he worked as a

printer for newspapers in Saint Louis,

Missouri; New York City; and Philadelphia,

Pennsylvania. In the late 1850s

and early 1860s he piloted steamboats

on the Mississippi.

Clemens also wrote humorous stories for

newspapers. In the 1860s he started

writing under the name Mark Twain. In

1865 he published a story called “The

Celebrated Jumping Frog of Calaveras

County.” It made him famous.

In the 1870s Twain settled with his family

in Hartford, Connecticut. There he

wrote his most famous books. He used

his experiences growing up on the Mississippi

River to write many of his stories.

His novel The Adventures of Tom

Sawyer (1876) is a story about a boy and

his friends in a small river town. The

Adventures of Huckleberry Finn (1884)

tells of a boy’s adventures as he floats

down the Mississippi on a raft. Huckleberry

Finn was his best book.

Late in life Twain lived mainly in

Europe with his family. He died in Redding,

Connecticut, on April 21, 1910.

Tyler, John

The 10th president of the United States,

John Tyler did not win a presidential

election. He took office after the death

of President William Henry Harrison in

1841.

Early Life

John Tyler was born on March 29,

1790, at Greenway, his family’s plantation

near Richmond, Virginia. He was

Mark Twain the son of Mary Armistead and John

122 Twain, Mark BRITANNICA STUDENT ENCYCLOPEDIA

Tyler, Sr., a judge and former governor

of Virginia.

After graduating from the College of

William and Mary in 1807, Tyler

became a lawyer at age 19. He married

Letitia Christian in 1813. The couple

had eight children.

Political Career

Tyler entered the Virginia legislature in

1811. In 1816 he was elected to the

U.S. House of Representatives. He

served again in the Virginia legislature

before becoming governor of Virginia in

1825. Two years later he was elected to

the U.S. Senate, where he served until

1836.

Although Tyler was a Democrat, he disagreed

with Democratic president

Andrew Jackson. He and many Southern

Democrats joined the Whig Party.

In 1840 the Whigs chose Tyler to run

for vice president under Harrison. Harrison

and Tyler won the election.

Presidency

President Harrison died just one month

after taking office. He was the first president

to die in office, and the Constitution

did not say whether the vice

president should become president or

just act as president. Tyler decided that

he was president.

March 29, January 18,

1790 1825 1840 1841 1845 1861 1862

Tyler is

born near

Richmond,

Virginia.

Tyler becomes

governor of

Virginia.

Tyler is

elected

vice president

under William

Henry

Harrison.

Tyler becomes

president after

Harrison dies.

Tyler leaves

office.

Tyler wins a

seat in the

Confederate

Congress.

Tyler dies in

Richmond,

Virgina.

T I M E L I N E

John Tyler was the 10th president of the

United States.

BRITANNICA STUDENT ENCYCLOPEDIA Tyler, John 123

Neither the Whigs nor the Democrats

supported Tyler. Still, he led Congress to

reorganize the Navy and to establish the

Weather Bureau. He ended an expensive

war against the Seminole people in

Florida. He also helped to stop a rebellion

against the state government of

Rhode Island in 1842. Finally, Tyler got

Congress to agree to take over the

Republic of Texas.

Tyler’s wife died in 1842. In 1844 Tyler

married Julia Gardiner. They had seven

children.

Later Years

For the presidential election of 1844

Tyler created his own political party, but

he soon dropped out of the race. He left

office in 1845.

Tyler was a slave owner, but before the

American Civil War (1861–65) he

wanted to keep the Union together.

When the war began, however, he

supported the South and was elected to

the Confederate House of Representatives.

Before taking office, he died in

Richmond on January 18, 1862.

#More to explore

Confederate States of America

• Harrison,William Henry • Jackson,

Andrew • United States

Typhoid Fever

Typhoid fever is a serious disease. It is

rare in wealthy countries but common

in poor ones. People with the disease

usually have a high fever for many days.

Other symptoms, or signs, of typhoid

fever include headache, stomach pain,

and weakness. A rash of rosy spots also

may appear on the body.

Tiny living things called bacteria cause

typhoid fever. The type of bacteria that

causes the disease lives only in humans.

It travels in the blood and attacks the

intestines. It passes from person to person

through water or food.

Typhoid fever may be prevented by

keeping water supplies clean.Washing

the hands before preparing food is

important, too. People also may get a

typhoid fever vaccine (a substance that

prevents the disease) from a doctor or a

nurse. People who do get the disease need

to be treated with drugs called antibiotics.

People who are not treated may die.

In the early 1900s a cook called Mary

Mallon spread typhoid fever to at least

51 people in the United States. She carried

the bacteria but did not get the disease.

She passed the bacteria to people

through food that she prepared. Mallon’s

actions earned her the nickname

Typhoid Mary.

#More to explore

Bacteria • Disease, Human

Typhus

Typhus is the name of several diseases

caused by tiny living things called bacteria.

The symptoms of typhus include

headache, fever, and rash. Lice, fleas,

mites, and ticks carry the types of bacteria

that cause typhus. These bloodsuckers

pass the bacteria to humans.

Tyler’s enemies

called him

“His Accidency.”

They

did not want

anyone to forget

that he

had become

president “by

accident.”

124 Typhoid Fever BRITANNICA STUDENT ENCYCLOPEDIA

To prevent typhus, people should keep

lice, fleas, mites, and ticks from getting

on their skin. People also can get a vaccine,

or substance that prevents the disease.

If a person does get typhus, drugs

called antibiotics can cure it.

#More to explore

Disease, Human

Tyrannosaurus

Rex

Tyrannosaurus rex, or T. rex, was one of

the largest and most ferocious predators

ever to walk on Earth. The name Tyrannosaurus

rex means “king of the tyrant

lizards.” T. rex was just one of the group

of dinosaurs called tyrannosaurs. The

tyrannosaurs were theropods, or meateating

dinosaurs that walked on their

two back legs.

When and Where

Tyrannosaurus rex Lived

T. rex lived about 80 to 65 million years

ago. Fossil remains of T. rex have been

found in the United States, Canada, and

Asia. Scientists believe that T. rex lived

in forests and in forest clearings.

Physical Features

T. rex could reach a length of 42 feet (13

meters) and weighed up to 8 tons. Its

huge head could reach 5 feet (1.5

meters) in length, and its skull alone

weighed up to 600 pounds (270 kilograms).

Its eyes allowed it to see forward

and to the sides. T. rex had about 60

teeth with sawlike edges. It had muscular

back legs, each with three clawed

toes. T. rex’s front legs were tiny but very

strong. Its tail was held off the ground.

Behavior

T. rex preyed on plant-eating dinosaurs.

It most likely lunged out from behind

trees in surprise attacks. It also may

have hunted in packs to bring down

much larger dinosaurs. Scientists

estimate that T. rex could run 20 miles

per hour (32 kilometers per hour) for

short distances. T. rex also may have

been a scavenger, feeding upon dead

animals.

#More to explore

Dinosaur

Tyrannosaurus rex

BRITANNICA STUDENT ENCYCLOPEDIA Tyrannosaurus Rex 125

Britannica

Student

Encyclopedia

Chicago • London • New Delhi • Paris • Seoul • Sydney • Taipei • Tokyo

Volume 14

2010 Britannica Student Encyclopedia

Copyright © 2010 by Encyclop.dia Britannica, Inc.

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All rights reserved. Copyright under International Copyright Union

No part of this work may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying,

recording, or by any information storage and retrieval system, without permission in writing from the publisher.

Library of Congress Control Number: 2009904642

Britannica may be accessed at http://www.britannica.com on the Internet.

International Standard Book Number: 978-1-61535-363-7

eBook edition January, 2010

The average year-round temperature

of Ulaanbaatar, the

capital of Mongolia, is only

27°F (–3° C).

(See Ulaanbaatar.)

The Underground Railroad was

a secret organization that

helped escaped slaves from the

Southern United States reach

places of safety in the North or

in Canada.

(See Underground Railroad.)

The main goal of the United

Nations, an organization of

almost all the world’s countries,

is world peace.

(See United Nations.)

The Milky Way galaxy contains

more than 100 billion stars.

(See Universe.)

The urine of birds and reptiles

is white and thick. The urine of

land insects is solid.

(See Urinary System.)

Uu

Uganda

Uganda is a country in East Africa. It

takes its name from Buganda, which was

a powerful African kingdom in the

1800s. Uganda’s capital is Kampala.

Geography

Uganda shares borders with Sudan,

Kenya, Tanzania, Rwanda, and the

Democratic Republic of the Congo.

Lake Victoria lies to the southeast. It is

the world’s second largest freshwater

lake, after Lake Superior in North

America.

Most of Uganda is on a plateau, or

raised flat area. A huge natural ditch

called theWestern Rift Valley runs along

the country’s western border. Mountains

rise in the west, north, and east. Uganda’s

rivers include the Victoria Nile and

the Albert Nile. Uganda has a warm

climate with rainy and dry seasons.

Plants and Animals

Scattered tropical rain forests grow in

southern Uganda. In the north tall

grasses and clumps of trees cover the

land.

Hippopotamuses and crocodiles live in

most of Uganda’s lakes. The country’s

wildlife also includes chimpanzees,

elephants, lions, leopards, rhinoceroses,

giraffes, and zebras. Rare mountain

gorillas live in a national park in the

southwest.

People

Dozens of different African peoples live

in Uganda. Those who speak Bantu languages

make up the largest part of the

population. The Ganda people form the

largest single group. Small numbers of

Mgahinga Gorilla National Park

in southwestern Uganda is home

to rare mountain gorillas.

4 Uganda BRITANNICA STUDENT ENCYCLOPEDIA

Asians, Europeans, and Arabs also live in

Uganda.

Uganda’s peoples speak more than 30

languages. English, Ganda (or Luganda),

and Swahili are the most common languages.

About two thirds of the people

are Christians. Many other Ugandans

practice Islam or traditional African

religions. Most people live in rural areas.

Economy

Most of Uganda’s people are farmers.

The main crops include coffee, tea, cotton,

and tobacco. People grow sweet

potatoes, corn, peanuts, and beans for

food. Farmers also raise cattle, sheep,

goats, pigs, chickens, ducks, and turkeys.

Fishing is another important source of

food.

Industry is a small part of Uganda’s

economy. Many industries process farm

products, including coffee, tea, tobacco,

sugar, and cooking oils. Uganda also

produces beer, soft drinks, cement,

metal products, shoes, soap, and fabrics.

The country’s mines provide copper,

cobalt, gold, and other minerals.

History

Small groups of farmers and herders

moved into the Uganda region hundreds

of years ago.West of Lake Victoria, the

Bunyoro kingdom gained power at the

end of the 1400s. By the 1800s, however,

the Buganda kingdom had become

the largest power in the region.

Arab traders reached the area in the

1840s. The first European explorers

came to Buganda in 1862. Missionaries

soon followed and began to teach Christianity.

Great Britain took over Buganda

in the 1890s.

In 1962 the region gained independence

as the Republic of Uganda. In 1971 a

military officer named Idi Amin seized

control of the government. He ruled the

country as a dictator, or a leader with

unlimited power. The military government

killed as many as 300,000 Ugandans

during Amin’s rule.

In 1979 Amin was forced to leave the

country after making an unsuccessful

attack on Tanzania. Uganda elected a

president in 1980, but the military took

control again in 1985. In 1986 a rebel

leader named Yoweri Museveni became

president. Other rebels tried to bring

down his government, but he remained

in power into the 21st century.

..More to explore

Kampala

Several houses stand on a hillside in a

mountainous area of Uganda. Most of the

country’s people have homes in rural areas.

Facts About

UGANDA

Population

(2008 estimate)

29,166,000

Area

93,065 sq mi

(241,038 sq km)

Capital

Kampala

Form of

government

Republic

Major cities

Kampala, Gulu,

Lira, Jinja, Mbale

BRITANNICA STUDENT ENCYCLOPEDIA Uganda 5

Ukraine

Ukraine is the second largest country in

Europe, after Russia. Ukraine’s capital is

Kiev.

Geography

Ukraine shares borders with Moldova,

Romania, Hungary, Slovakia, Poland,

Belarus, and Russia. The Black Sea and

the Sea of Azov lie to the south.

Almost all of Ukraine is flat. The grassland

that covers the central and southern

parts of the country is called the steppe.

In northern Ukraine are the Pripet

Marshes, the largest swamp in Europe.

The Carpathian Mountains rise in the

west. The Crimean Mountains cross the

Crimean Peninsula, a piece of land that

extends south into the Black Sea.

Ukraine’s longest river is the Dnieper.

Most of Ukraine has warm summers and

cold winters. It rains mainly in June and

July.

Plants and Animals

Most of Ukraine’s forests are in the

mountains in the west. Some trees grow

among the swamplands and in central

Ukraine. The southern grassland has few

trees. The country’s animals include

deer, wolves, bears, foxes, wildcats, beavers,

weasels, and badgers.

People

Most of Ukraine’s people are ethnic

Ukrainians, but Russians form an

important minority group. There are

also small groups of Moldovans, Tatars,

and Belarusians. Ukrainian is the main

language. Most people live in cities or

towns.

About half the people of Ukraine follow

some form of Eastern Orthodox Christianity.

Others are Ukrainian Catholics,

Roman Catholics, Protestants, or Muslims.

About one Ukrainian in six does

not follow any religion.

Cliffs on the Crimean Peninsula overlook the

Black Sea. The peninsula is the most southern

part of Ukraine.

6 Ukraine BRITANNICA STUDENT ENCYCLOPEDIA

Economy

Manufacturing and mining are both

important to Ukraine’s economy. Factories

produce iron and steel, locomotives,

tractors, chemicals, and other goods.

Mines provide manganese, coal, iron

ore, salt, sulfur, and other minerals.

Ukraine also has reserves of natural gas

and oil.

Farming is important to the economy,

too. The main crops are potatoes, sugar

beets, wheat, barley, corn, rye, and oats.

Farmers also raise cattle, pigs, sheep, and

goats.

History

Tribes of people called Slavs arrived in

what is now Ukraine during the 400s and

500s. Viking invaders called Varangians

later mixed with the Slavs. They set up a

state that became the powerful kingdom

of Kievan Rus. Kievan Rus lost power

whenMongols invaded in the 1200s.

Poles and Cossacks

In the 1300s Lithuania took control of

most of Ukraine. Poland ruled most of

Ukraine after 1569. The Poles made

many Ukrainians into serfs, or farmers

who had to work on land that they did

not own.

Some serfs escaped and joined a military

force called the Cossacks. In 1648 the

Cossacks led a fight against Polish rule.

The Cossacks asked Russia to help them

defeat the Poles. The Cossacks won

independence from Poland, but their

new state soon became part of the Russian

Empire.

Soviet Control

In the 1700s Russia slowly gained control

over almost all of Ukraine. By 1922

Ukraine had become part of the newly

formed Soviet Union. The Soviets took

over Ukraine’s farms. During the 1930s

about 5 to 7 million Ukrainians died

from starvation.

During WorldWar II Germany invaded

Ukraine. German forces made millions

of Ukrainians into slaves and murdered

about 600,000 Ukrainian Jews. The

Soviets drove the Germans out of

Ukraine in 1944.

Independence

In 1991 the Soviet Union broke apart,

and Ukraine declared its independence.

In 2004 many Ukrainians protested

when Viktor Yushchenko lost the presidential

election. They thought the election

had been unfair. Ukraine then held

a second election, and Yushchenko won.

..More to explore

Crimea • Kiev • Union of Soviet

Socialist Republics

Folk dancers in traditional dress perform on

a street in Ukraine.

Facts About

UKRAINE

Population

(2008 estimate)

46,222,000

Area

233,062 sq mi

(603,628 sq km)

Capital

Kiev

Form of

government

Republic

Major cities

Kiev, Kharkiv,

Dnipropetrovsk,

Odessa, Donetsk

BRITANNICA STUDENT ENCYCLOPEDIA Ukraine 7

Ulaanbaatar

Population

(2008 census)

1,031,200

Ulaanbaatar is the capital of Mongolia,

a country in central Asia. It is the

largest city in Mongolia by far. It lies

on the Tuul River. Ulaanbaatar is one of

the world’s coldest capitals. Its average

year-round temperature is only 27° F

(.3° C).

Ulaanbaatar is one of Mongolia’s industrial

centers. Factories in the city make

food products, fabrics, carpets, leather

goods, and a luxury fiber called cashmere.

Many people in Ulaanbaatar work

for the government or in trade or other

service industries.

Buddhists built a religious center called

the Da Khure monastery in what is

now Ulaanbaatar in 1639. Over time a

city grew around the monastery. It

became a trade center on a route

between China and Russia.

China controlled Mongolia for hundreds

of years. In 1911 Mongolia

became an independent country. Ulaanbaatar

was made its capital in 1924. The

city grew rapidly during the 1900s.

..More to explore

Mongolia

Ulster

Ulster was an ancient kingdom of Ireland.

It covered the northern part of the

island of Ireland. The name Ulster is

now commonly used for Northern Ireland,

a part of the United Kingdom.

Ulster was one of five Irish kingdoms

created about 2,000 years ago by people

called the Celts. In its early history, it

was the most powerful of the kingdoms.

It was ruled by Roman Catholic kings.

England took control of Ireland in the

1100s. In the late 1500s Ulster rebelled

against England, but it was defeated.

The English king then sent Protestant

settlers from Scotland and England to

Ulster. Ulster changed from Catholic to

mostly Protestant. The religious differences

led to fighting.

Elderly people gather outside a Buddhist

religious center in Ulaanbaatar, Mongolia.

8 Ulaanbaatar BRITANNICA STUDENT ENCYCLOPEDIA

In the early 1900s southern Ireland

moved toward independence from Great

Britain. The Protestants of Ulster

wanted to remain part of Britain. In

1920 Britain divided the island. Six of

Ulster’s nine counties remained under

British rule. They became Northern

Ireland. The other three counties joined

the new country of Ireland.

#More to explore

Celt • Ireland • Northern Ireland

Underground

Railroad

The Underground Railroad was not an

actual railway. Instead, it was a secret

organization that existed in the United

States before the CivilWar. The people

of the Underground Railroad helped

escaped slaves from the South to reach

places of safety in the North or in

Canada.

The Underground Railroad used railway

terms as code words. The routes to freedom

were called “lines.” The hiding

places on the lines were called “stations.”

The people who moved or hid the slaves

were called “conductors.” The slaves

themselves were sometimes called

“freight.”

The Underground Railroad had to be

secret because it was against the law.

Laws called the Fugitive Slave acts protected

slaveholders’ rights even in states

that did not allow slavery. The people

who ran the Underground Railroad were

abolitionists—they wanted to abolish, or

end, slavery in all states.

Many Underground Railroad conductors

were followers of the Quaker religion.

The Quaker leader Thomas

Garrett is believed to have helped about

2,700 slaves escape. Other conductors

were Northern blacks. Harriet Tubman,

a former slave, led hundreds of slaves to

freedom.

The heaviest activities of the

Underground Railroad were in

Pennsylvania, Ohio, Indiana, New York,

and the New England states. Most

routes ended in Canada. Estimates of

the number of slaves who “rode” the

Underground Railroad range from

40,000 to 100,000. The Railroad’s

activities ended with the beginning of

the Civil War in 1861.

#More to explore

Abolitionist Movement • Fugitive Slave

Acts • Quaker • Slavery • Tubman,

Harriet

A painting shows how the Underground

Railroad in the United States moved

enslaved Africans to freedom in the dark of

night.

BRITANNICA STUDENT ENCYCLOPEDIA Underground Railroad 9

Unicorn

#see Animals, Legendary.

Unidentified

Flying Object

(UFO)

An unidentified flying object, or UFO,

is anything in the sky that cannot be

explained by the person who sees it.

Some people think that UFOs are alien

spaceships. But most scientists say that

UFOs can be explained in much more

ordinary ways.

Descriptions of UFOs have ranged from

glowing wheels to colored balls of light

to cigar-, crescent-, or disk-shaped

objects. A sighting of disk-shaped UFOs

in the 1940s led to the creation of the

term flying saucers. It then became

popular to call all UFOs flying saucers.

The U.S. government has kept records

of thousands of UFO sightings. These

records include photos of UFOs and

recordings of interviews with people

who claim to have seen them. In the

1950s scientists chosen by the government

studied hundreds of sightings.

Most of the sightings turned out to be

space objects, such as stars, bright planets,

or meteors. Many other sightings

were aircraft, birds, or hot gases. Often

these sightings happened in unusual

weather conditions.

The scientists’ findings did not stop

UFO reports, however. By the mid–

1960s UFO sightings were more numerous

than ever. The U.S. government

continued to say that UFOs were not

evidence of alien life. Most scientists

agreed. But some UFO sightings

remained unexplained. Even today a few

scientists believe that some UFOs could

be visitors from outer space.

Union of Soviet

Socialist

Republics

The Union of Soviet Socialist Republics

(U.S.S.R.), or Soviet Union, was the

first country to form a government and

an economy based on the system known

as Communism. The Soviet Union was

in existence for only about 70 years,

from 1922 to 1991. For much of that

time, however, it was one of the most

powerful countries in the world.

Clouds can often form strange shapes.

Some people may see such a cloud and

think that it looks like a flying saucer.

10 Unicorn BRITANNICA STUDENT ENCYCLOPEDIA

Land

The Soviet Union was the largest country

that ever existed. It covered more

than 8.6 million square miles (22.3 million

square kilometers) in Europe and

Asia—almost two and one half times the

area of the United States.

The Soviet Union was made up of 15

states. The states were called republics.

The largest and most powerful republic

was the Russian Soviet Federated Socialist

Republic, which is now called Russia.

The modern names for the other republics

are Estonia, Latvia, Lithuania,

Belarus, Ukraine, Moldova, Georgia,

Armenia, Azerbaijan, Kazakhstan, Turkmenistan,

Uzbekistan, Tajikistan, and

Kyrgyzstan. The capital of the Soviet

Union was Moscow, which was also the

capital of Russia.

People

In its last years, the Soviet Union had

the world’s third-largest population—

more than 290 million people. The

country had more than 100 groups of

different peoples. Ethnic Russians made

up the largest group by far. The nextlargest

groups were Ukrainians, Uzbeks,

Belarusians, and Kazakhs. Russian was

the official language, but more than 200

other languages existed in the country.

The Soviet government did not approve

of religion. Even so, the Russian Orthodox

Christian church survived. There

were also many Muslims, or followers of

Islam, in some republics.

During the time the Soviet Union

existed, millions of people moved from

farms to cities. By 1991, two out of

The Russian republic was by far the largest of the 15 republics that made up the Soviet

Union.

BRITANNICA STUDENT ENCYCLOPEDIA Union of Soviet Socialist Republics 11

every three Soviet citizens lived in a city.

Moscow, Leningrad (now Saint Petersburg),

and Kiev (now in Ukraine) were

the largest cities.

Culture

The government of the Soviet Union

controlled all parts of life in the country.

The people were not allowed to speak

openly to oppose the government. During

the late 1920s and 1930s the government

even put a stop to free artistic

expression. Artists and writers were

allowed to say only good things about

the Soviet system. The government put

many artists and writers in prison. Others

left the country.

A few Soviet writers still produced great

work. Boris Pasternak won the Nobel

prize for literature in 1958, and Aleksandr

Solzhenitsyn won it in 1970. Pasternak

had to refuse the award, and

Solzhenitsyn was forced to leave the

country.

Economy

During its most powerful period, the

Soviet Union had one of the world’s

strongest economies. Agriculture, mining,

and heavy industry all made big

contributions to national wealth. The

government completed many large

projects such as dams and canals.

According to Communist teachings,

individuals should not be allowed to

own businesses. So the government

owned almost all businesses and factories

in the Soviet Union. Communist

Party leaders decided what kinds of

products would be made and how much

the people would pay for them. The

system led to shortages of many of the

products that people needed.

The Communist system was also supposed

to give farmers and workers a fair

share of the country’s wealth. However,

farmers suffered greatly when the gov-

The Soviet government built plain high-rise

apartment buildings in Moscow and other

big cities. The buildings were needed to

house the many people who moved to the

cities from farms.

“For the Defense of the U.S.S.R.”

is the message of a 1929 poster.

It shows factories, warplanes,

and soldiers on the march.

12 Union of Soviet Socialist Republics BRITANNICA STUDENT ENCYCLOPEDIA

ernment took their land and created

large farms called collective farms. By

the 1970s the Soviet Union had to buy

food from other countries to feed its

people.

History

The Soviet Union was originally the

Russian Empire. The tsar, or emperor,

fell from power in a revolution that took

place in 1917. Later in the same year a

group called the Bolsheviks came to

power. This group, later renamed the

Communist Party, fought other Russians

in a civil war that lasted from 1918 to

1920. Vladimir Lenin led the Communists.

The Communists won the war.

Early Years

On December 20, 1922, the Communists

created the Union of Soviet Socialist

Republics. Russia was one of its

republics. The other republics were

mostly regions of the former Russian

Empire. They were home to various

non-Russian groups.

Lenin died in 1924. A few years later, a

Communist Party leader named Joseph

Stalin came to power. Stalin was one of

the cruelest rulers who ever lived. He

killed farmers who did not want collective

farms. He sold crops to foreign

countries and let his own people starve.

During the 1930s he caused as many as

10 million people in the Soviet Union to

die.

WorldWar II

In 1939, just beforeWorldWar II

began, Germany and the Soviet Union

secretly agreed not to attack each other.

Germany then invaded Poland, which

started the war. Germany and the Soviet

Union divided Poland between them.

The Soviet Union also took Latvia,

Lithuania, and Estonia at this time and

made them Soviet republics.

In June 1941, however, Germany broke

the agreement and invaded the Soviet

Union. The Soviet Union then joined

the United States and Great Britain to

fight Germany.

The Soviet Union suffered terribly during

the war. By the time Germany surrendered

in 1945 more than 20 million

Soviet people had died.

ColdWar

Despite all the damage it had suffered,

the Soviet Union was still the greatest

power in Europe afterWorldWar II.

While fighting the Germans, Soviet

troops moved into many countries in

eastern Europe. Between 1945 and 1948

the Soviets set up Communist governments

in these countries. They con-

The Communist Party leader Vladimir Lenin

speaks to an outdoor gathering in 1920.

BRITANNICA STUDENT ENCYCLOPEDIA Union of Soviet Socialist Republics 13

trolled these governments. This activity

worried many people in other countries,

particularly the United States. Both

countries built up their military forces.

The rivalry between them came to be

known as the ColdWar.

The United States and the Soviet Union

both developed nuclear weapons. Many

people were afraid that this would lead

to nuclear war. But neither country ever

used the weapons.

Conditions improved for the Soviet

people following Stalin’s death in 1953.

Over the next few years Nikita Khrushchev

came to power. Khrushchev introduced

some reforms that angered other

Communist party leaders. In 1964 he

lost power.

Some eastern European countries tried

to take advantage of the reforms. They

rose up against Soviet rule. To stop the

uprisings, the Soviet Union invaded

Hungary in 1956 and Czechoslovakia in

1968.

The Soviets invaded Afghanistan in

1979. Afghanistan is an Asian country

that bordered the Soviet Union. Rebels

there were trying to overthrow a Communist

government. The United States

supported the rebels. In 1989 the Soviet

Union left Afghanistan in defeat.

Breakup

In 1985 Mikhail Gorbachev came to

power. Gorbachev wanted to build a

stronger economy and a freer society.

His policies were called glasnost, which

means “openness,” and perestroika,

which means “restructuring.” But Gorbachev

soon learned that the more freedom

his people had, the more they

wanted. Beginning in 1987 people in

some of the Soviet republics began to

demand independence.

In 1989 a series of almost completely

peaceful revolutions began. The eastern

European countries gained independence

from Soviet control. During 1991

the Soviet republics also gained their

independence. On the last day of that

year, the Soviet Union came to an end.

Fifteen separate countries replaced it.

#More to explore

ColdWar • Communism • Lenin,

Vladimir Ilich • Moscow • Russia

• Russian Revolution • Stalin, Joseph

Each May Day (May 1) the Soviet government

paraded missiles and other military

weapons through Red Square in central

Moscow.

14 Union of Soviet Socialist Republics BRITANNICA STUDENT ENCYCLOPEDIA

United Arab Emirates

The United Arab Emirates is a small,

rich country in the Middle East. The

capital is Abu Dhabi.

Geography

The country is a union of seven small

kingdoms, or emirates. The emirate

called Abu Dhabi takes up most of the

country’s land. It stretches along the

Persian Gulf, to the north. The other six

emirates are in the northeast. The country

shares borders with Saudi Arabia and

Oman. Most of the land is a flat desert.

Plants and Animals

Few plants grow in the desert. Date

palm, mango, and guava trees grow near

the coast. Snakes, lizards, foxes, hares,

and gerbils live in the country.

People

Less than a quarter of the people in the

United Arab Emirates are citizens. Most

people are workers from other countries.

Arabs make up about half of the population.

South Asians form the next largest

group. Most people are Muslims. Arabic

is the main language.

Economy

The United Arab Emirates’ economy

depends on the sale of oil and natural

gas. The country also produces chemicals,

clothing, cement, metals, food

products, and minerals.

History

For hundreds of years the region was

divided among many tribes and kingdoms.

In the 1800s the main tribal rulers

signed peace agreements, or truces,

with Great Britain. The region then

became known as the Trucial States. The

British left the region in 1971. Six emirates

then joined together to form the

United Arab Emirates. In 1972 a seventh

emirate joined the country.

..More to explore

Abu Dhabi • Arabs • Middle East

Boys get ready for a camel race in the

United Arab Emirates.

Facts About

UNITED ARAB

EMIRATES

Population

(2008 estimate)

4,660,000

Area

32,280 sq mi

(83,600 sq km)

Capital

Abu Dhabi

Form of

government

Federation of

seven emirates

Major cities

Dubayy, Abu

Dhabi, Ash-

Shariqah,

Al-!Ayn, !Ajman

BRITANNICA STUDENT ENCYCLOPEDIA United Arab Emirates 15

United Kingdom

The United Kingdom is a country of

western Europe. It is made up of four

parts: England, Scotland, Wales, and

Northern Ireland. The country’s full

name is the United Kingdom of Great

Britain and Northern Ireland. Sometimes

the country is called Great Britain,

or just Britain. The capital of the United

Kingdom is London, in southeastern

England.

Geography

The United Kingdom is an island

country in the Atlantic Ocean. It lies off

the northwestern coast of mainland

Europe. The country has land on two

main islands. The island of Great Britain

contains England, Scotland, andWales.

England covers most of the southern two

thirds of Great Britain. Scotland takes up

the northern third.Wales lies on the

southwestern part of Great Britain.

The island of Ireland is west of Great

Britain. Northern Ireland is in the

northeastern part of this island. The

country called Ireland takes up the rest

of the island. It is not part of the United

Kingdom.

Plants and Animals

The United Kingdom has forests in

northeastern Scotland and southeastern

England. Common trees include oak,

elm, ash, beech, pine, and birch. Some

parts of Scotland and Northern Ireland

have large areas of peat moss and

heather.

The United Kingdom has quiet villages, but

most of its people live in large cities.

16 United Kingdom BRITANNICA STUDENT ENCYCLOPEDIA

Deer, badgers, otters, foxes, and weasels

live in rural areas. Rabbits, rodents,

hedgehogs, moles, and shrews are common.

Birds include sparrows, blackbirds,

chaffinches, and starlings.

People

The people of the United Kingdom are

called the British. Most of them are

descendants of early settlers from mainland

Europe. More than four fifths of

the people live in England. The population

also includes people from places

that the United Kingdom once ruled as

colonies. Many of these people have

roots in India, Pakistan, Bangladesh, the

West Indies, and Africa.

English is the most common language in

the United Kingdom. Some people

speakWelsh, Scottish Gaelic, or Irish

Gaelic.

About two thirds of the people are

Christian. Of these, most belong to

Protestant churches. The United Kingdom

also has groups of Muslims, Hindus,

Sikhs, and Jews.

Economy

International trade, finance, and

insurance are important to the United

Kingdom’s economy. The country

before

300 BC AD 927 1536 1707 1801 1921 1999

Celts settle in

Great Britain

and Ireland.

The first united

English

kingdom is

established.

Wales is united

with England.

Scotland is

united with

England and

Wales.

Ireland is

added, forming

the United

Kingdom.

Most of Ireland

splits from the

United

Kingdom.

Wales,

Scotland, and

Northern

Ireland get

parliaments.

T I M E L I N E

The Scottish Exhibition and Conference

Centre in Glasgow, Scotland, attracts visitors

from all over the United Kingdom. It

hosts business meetings and public events,

including concerts and dance performances.

BRITANNICA STUDENT ENCYCLOPEDIA United Kingdom 17

exports, or sells to other countries,

electrical equipment, automobiles,

aircraft, petroleum (oil), and iron and

steel products. The United Kingdom

also has important paper, printing, and

publishing industries. The main crops

include barley, wheat, sugar beets, and

potatoes. Farmers also raise cattle,

sheep, and pigs.

History

The United Kingdom was invaded

many times in its early history. By

about 300 BC people called Celts had

arrived on the islands of Great Britain

and Ireland. They came from mainland

Europe. The Romans came in the 1st

century BC. England and Wales were

part of the Roman Empire until the AD

400s. Then peoples called Angles,

Saxons, and Jutes invaded from

northern Germany. They settled

throughout England. Eventually all the

people of England came to be known as

Anglo-Saxons.

In the 700s and 800s Vikings from

northern Europe raided the coasts of

England. In the late 800s the Anglo-

Saxons defeated the Vikings. Then, in

the 900s, the Anglo-Saxons established a

united English kingdom for the first

time.

Growth of the Kingdom

The English kingdom grew through

conquests over hundreds of years. In the

late 1200s the king of England seized

Wales. Before that,Wales had been a

collection of Celtic kingdoms. In 1536

the English Parliament, a group of lawmakers,

officially unitedWales with

England.

The ruins of a Roman Catholic abbey stand

in a field in northern England. King Henry

VIII broke away from the Roman Catholic

church in the 1500s. He ordered Catholic

monks to leave the monasteries where they

lived and worked. He also founded a new

Protestant church called the Church of

England. Today most people in the United

Kingdom are Protestant.

Guards march in front of Buckingham Palace,

the London home of the king or queen

of the United Kingdom. The country is a

constitutional monarchy. This means that

though there is a king or queen, the real

power to rule the country rests with members

of the Parliament, who are elected by

the people.

Facts About

UNITED

KINGDOM

Population

(2008 estimate)

61,446,000

Area

93,635 sq mi

(242,514 sq km)

Capital

London

Form of

government

Constitutional

monarchy

Major cities

London,

Manchester, Birmingham,

Leeds,

Newcastle

18 United Kingdom BRITANNICA STUDENT ENCYCLOPEDIA

Scotland fought many battles against

England to keep its independence. In

1603 Scotland and England were united

under one king, but Scotland kept its

own, separate parliament. Then, in

1707, the parliaments of Scotland and

Kings and Queens of England

Name Nationality or Family Years of Reign

Athelstan Saxon 925–939

Edmund I Saxon 939–946

Eadred Saxon 946–955

Eadwig Saxon 955–959

Edgar Saxon 959–975

Edward the Martyr Saxon 975–978

Ethelred II the Unready Saxon 978–1013

Sweyn Forkbeard Danish 1013–14

Ethelred II the Unready Saxon 1014–16

Edmund II Ironside Saxon 1016

Canute Danish 1016–35

Harold I Harefoot Danish 1035–40

Hardecanute Danish 1040–42

Edward the Confessor Saxon 1042–66

Harold II Saxon 1066

William I the Conqueror Norman 1066–87

William II Norman 1087–1100

Henry I Norman 1100–35

Stephen Blois 1135–54

Henry II Plantagenet 1154–89

Richard I Plantagenet 1189–99

John Plantagenet 1199–1216

Henry III Plantagenet 1216–72

Edward I Plantagenet 1272–1307

Edward II Plantagenet 1307–27

Edward III Plantagenet 1327–77

Richard II Plantagenet 1377–99

Henry IV Plantagenet: Lancaster 1399–1413

Henry V Plantagenet: Lancaster 1413–22

Henry VI Plantagenet: Lancaster 1422–61

Edward IV Plantagenet: York 1461–70

Henry VI Plantagenet: Lancaster 1470–71

Edward IV Plantagenet: York 1471–83

Edward V Plantagenet: York 1483

Richard III Plantagenet: York 1483–85

Henry VII Tudor 1485–1509

Henry VIII Tudor 1509–47

Edward VI Tudor 1547–53

Mary I Tudor 1553–58

Elizabeth I Tudor 1558–1603

BRITANNICA STUDENT ENCYCLOPEDIA United Kingdom 19

England were joined. The newly united

country, which consisted of England,

Scotland, andWales, was called the

kingdom of Great Britain. The people of

the kingdom were called the British.

England conquered much of Ireland in

the late 1100s. The people of Ireland,

like the people of Scotland, resisted

English rule. But by the end of the

1600s England had firm control of the

Kings and Queens of England and Scotland

Name Family Years of Reign

James I Stuart 1603–25

Charles I Stuart 1625–49

Oliver Cromwell, Lord Protector 1653–58

Richard Cromwell, Lord Protector 1658–59

Commonwealth (No King or Queen)

Name Years of Rule

Charles II Stuart 1660–85

James II Stuart 1685–88

William III and Mary II Orange/Stuart 1689–94

William III Orange 1694–1702

Kings and Queens of England and Scotland

Name Family Years of Reign

Kings and Queens of Great Britain (England and Scotland)

Name Family Years of Reign

Anne Stuart 1702–14

(Kingdom of Great Britain was

formed in 1707)

George I Hanover 1714–27

George II Hanover 1727–60

Kings and Queens of the United Kingdom

Name Family Years of Reign

George III Hanover 1760–1820

(United Kingdom was formed

in 1801)

George IV Hanover 1820–30

William IV Hanover 1830–37

Victoria Hanover 1837–1901

Edward VII Saxe-Coburg-Gotha 1901–10

George V Windsor 1910–36

Edward VIII Windsor 1936

George VI Windsor 1936–52

Elizabeth II Windsor 1952–

20 United Kingdom BRITANNICA STUDENT ENCYCLOPEDIA

island. Ireland was officially joined to

England, Scotland, andWales in 1801.

It was called the United Kingdom of

Great Britain and Ireland.

The British Empire

Many years earlier England had begun

to establish settlements called colonies in

other parts of the world. People from

England started settling in North

America and Asia in the 1600s. Later

others settled in Africa and other places.

All the colonies and lands that were

ruled by England came to be known as

the British Empire.

Great Britain lost its American colonies

as a result of the American Revolution

(1775–83). But the United Kingdom

still became one of the richest and most

powerful countries in the world. During

the reign of Queen Victoria (1837–

1901) the British Empire included more

than one fourth of the world’s people.

Conflict in Ireland

Many Irish people did not want Ireland

to be part of the United Kingdom. One

concern was that most Irish people were

Roman Catholic while most English

were Protestant. The English government

established anti-Catholic laws in

both Britain and Ireland. For example,

Catholics were not allowed to hold public

office for many years.

After years of fighting, most of Ireland’s

counties split from the United Kingdom

in 1921. They formed the Irish Free

State (now Ireland). But six northern

counties remained part of the United

Kingdom as Northern Ireland. The

country was renamed the United Kingdom

of Great Britain and Northern Ireland.

Some people in Northern Ireland

continued to fight against British rule

through the 20th century.

Later Years

The United Kingdom was on the winning

side in both WorldWar I (1914–

18) and WorldWar II (1939–45). After

WorldWar I Britain won new lands

from the defeated countries as the result

of peace treaties. Prime MinisterWinston

Churchill gave Britain strong leadership

duringWorldWar II. But British

cities were heavily damaged. The United

Kingdom spent years rebuilding its

economy.

AfterWorldWar II Britain gave up most

of its lands in other parts of the world.

Almost all the former colonies, however,

chose to maintain ties with Britain.

They remained members of a British

organization called the Commonwealth.

For many years the people ofWales,

Scotland, and Northern Ireland asked

for more self-rule. During the 1990s the

British government finally allowed the

three to form their own parliaments.

The national Parliament in London,

however, continued to govern the

United Kingdom as a whole.

#More to explore

Anglo-Saxon • Celt • Empire • England

• Europe • London • Northern Ireland

• Parliament • Rome, Ancient

• Scotland • Vikings •Wales •World

War I •WorldWar II

BRITANNICA STUDENT ENCYCLOPEDIA United Kingdom 21

United Nations

The United Nations is an organization

that includes almost all the world’s

countries, or nations. It is called the UN

for short. By the 21st century the

United Nations had more than 190

members. The main goal of the United

Nations is world peace. The United

Nations also works to reduce poverty

and suffering and to improve people’s

lives in other ways.

Functions

The United Nations tries to find peaceful

solutions to disagreements between

countries. If fighting breaks out, the

United Nations sometimes sends in

military troops to try to stop it.

After a war, UN organizations provide

money to help countries rebuild. They

also give poor countries money to help

build up their economies.

The United Nations helps refugees—

people who have left their countries to

avoid danger or mistreatment. The

United Nations also tries to protect

human rights. The United Nations

Universal Declaration of Human

Rights, written in 1948, describes those

rights. The United Nations also tries to

make sure that everyone gets equal

treatment regardless of race, sex,

language, or religion.

Divisions

The United Nations has six main parts.

They are the General Assembly, the

Security Council, the International

Court of Justice, the Secretariat, the

Economic and Social Council, and the

Trusteeship Council. The Trusteeship

Council is no longer active.

The General Assembly discusses all

kinds of issues that affect member

countries. It has representatives from

UN members. Each member has one

vote. To decide important questions, at

least two thirds of the members must

agree.

The Security Council looks into disagreements

between countries and suggests

ways to settle them peacefully.

Only 15 countries belong to the Security

Council at any one time. Five countries

belong permanently. They are the

United States, Great Britain, France,

Russia, and China. All five permanent

members must agree before the Security

Council can take action.

The International Court of Justice hears

disputes between countries. It is commonly

called theWorld Court. Any

member country can bring a case before

the court, which has 15 judges.

United Nations troops patrol an area in

order to help keep the peace.

22 United Nations BRITANNICA STUDENT ENCYCLOPEDIA

The Secretariat helps to carry out UN

decisions. People from almost every

member country work in its offices. An

official called the secretary-general runs

the Secretariat and speaks for the United

Nations.

The Economic and Social Council tries

to improve social services such as health

and education.Other groups called

specialized agencies help it in its work.

History

The United States, Great Britain, and

the Soviet Union planned the United

Nations. They wanted a new group to

take the place of the League of Nations.

The League had been formed to keep

peace afterWorldWar I (1914–18).

However, it was not powerful enough to

preventWorldWar II (1939–45).

In April 1945, near the end ofWorld

War II, people from 50 countries met in

San Francisco, California, to organize

the United Nations. In June they completed

the United Nations Charter, or

founding document. On October 24,

1945, the United Nations officially

began work.

#More to explore

Human Rights • League of Nations

• Refugee •WorldWar II

Some United Nations Agencies and Programs

Specialized Agencies Abbreviation Goals

International Labour ILO To improve working conditions for

Organization workers worldwide

Food and Agriculture FAO To improve farming, forestry, and

Organization of the UN fishing practices; to ensure that all

people have enough to eat

UN Educational, Scientific UNESCO To promote education for all; to protect

and Cultural Organization nature and the world’s cultures; to

promote international cooperation in

science; to ensure freedom of speech

World Health Organization WHO To ensure all people are as healthy

as possible

World Bank Group To give loans and technical help to

developing countries

Other Programs and Funds

United Nations Environment UNEP To help countries protect the

Programme environment

United Nations Children’s Fund UNICEF To help children worldwide be safe,

healthy, and educated

Office of the United Nations UNHCR To protect refugees (people who were

High Commissioner for forced to leave their country)

Refugees

World Food Programme WFP To get emergency food supplies to

people who need them

Source: United Nations

BRITANNICA STUDENT ENCYCLOPEDIA United Nations 23

United States

Established in 1776, the United States is

young compared to many other countries.

Yet by the 1900s the United States

had grown into a world power. The

capital is Washington, D.C.

Geography

The United States is the fourth largest

country in the world (after Russia,

Canada, and China). It extends across

North America from the Atlantic Ocean

on the east to the Pacific Ocean on the

west. The United States is made up of

50 states and the District of Columbia.

Forty-eight of the states lie between

Canada on the north and Mexico and

the Gulf of Mexico on the south. The

49th state, Alaska, lies northwest of

Canada. The 50th state, Hawaii, is a

group of islands in the Pacific Ocean.

The landscape of the United States

ranges from rugged mountains to flat

prairies and from moist rain forests to

dry deserts. The mountain ranges

include the Rocky Mountains and the

Sierra Nevada in the west and the Appalachian

Mountains in the east. Between

the Appalachians and the Rocky Mountains

is a vast lowland region that

includes the Great Plains. The highest

point in the country is Mount McKinley,

in Alaska. It is 20,320 feet (6,194

meters) high. The lowest point is Death

Valley, in the California desert. It lies

282 feet (86 meters) below sea level.

The United States has some of the largest

and most useful rivers and lakes in

A nighttime view of Washington,

D.C., shows the Lincoln Memorial

in the foreground, the tall

Washington Monument, and the

U.S. Capitol in the background.

Boaters enjoy a view of Yosemite

Falls in Yosemite National Park

in California.

24 United States BRITANNICA STUDENT ENCYCLOPEDIA

BRITANNICA STUDENT ENCYCLOPEDIA United States 25

the world. The longest rivers are the

Mississippi and the Missouri. They join

in the middle of the country. The combined

Mississippi-Missouri river system

is 3,710 miles (5,971 kilometers) long.

The five Great Lakes form the largest

connected area of freshwater on Earth.

The climate of the United States is as

varied as its land. It ranges from Arctic

cold in Alaska to tropical warmth in

Hawaii and southern Florida.

Plants and Animals

Forests in the eastern United States have

pine, hemlock, oak, hickory, birch, and

maple trees. Pine, fir, and spruce forests

are common in the Rocky Mountains

and along the Pacific coast. Grasslands

cover large parts of the central plains.

Sagebrush, yucca, and cactus are common

in the deserts of the Southwest.

The animals of the forest include bears,

elk, deer, foxes, bobcats, beavers, opossums,

and raccoons. Coyotes, prairie

dogs, jackrabbits, and a few bison (buffalo)

live on the grasslands. Desert animals

include snakes, lizards, scorpions,

and roadrunners.

People

The United States is made up of people

from many backgrounds. Whites make

up more than 70 percent of the population.

They have roots in Great Britain,

Ireland, Germany, Italy, Poland, Russia,

Sweden, and other European countries.

The two largest minority groups are

African Americans and Hispanic Americans.

Asian Americans, Pacific Islanders,

and Native Americans make up small

groups. Most Americans speak English.

The country also has many Spanish

speakers because of its large Hispanic

population.

More than four fifths of the population

is Christian. Protestants are the largest

Christian group, followed by Roman

Catholics. Other people practice Islam,

Judaism, Buddhism, and Hinduism.

More than three fourths of the people

live in or near cities. New York City, on

Prairies once covered large parts of the

central United States. Much of the land is

now used for farming or grazing. But there

are still areas where grasses cover the hills.

A group of white birds called ibises looks

for food in the Okefenokee Swamp in the

U.S. state of Georgia.

Facts About

THE UNITED

STATES

Population

(2008 estimate)

305,146,000

Area

3,616,236 sq mi

(9,366,008 sq

km)

Capital

Washington, D.C.

Form of

government

Republic

Major cities

New York, Los

Angeles, Chicago,

Houston,

Philadelphia,

Phoenix

26 United States BRITANNICA STUDENT ENCYCLOPEDIA

the East Coast, is one of the largest cities

in the world. Los Angeles, California,

and Chicago, Illinois, are the country’s

next largest cities.

Economy

The United States is a great economic

power. Service industries make up the

largest part of the economy. They

include finance, health care, education,

and tourism. Major manufactured products

include iron and steel, chemicals,

electronics, motor vehicles, aircraft, and

food.

The United States is rich in resources.

Its farmlands produce corn, soybeans,

wheat, cotton, and many other crops

that are sold to countries all over the

world. The United States is among the

world’s leading producers of several

minerals, including copper, silver, zinc,

gold, coal, petroleum (oil), and natural

gas. Forestry and fishing are important

industries, too.

History

The first people to live in the Americas

were the Native Americans. The first

Native Americans probably came from

Asia beginning about 60,000 years ago.

By the 1400s there were about 200 different

groups of Native Americans living

on the land that became the United

States.

The history of the Americas changed

forever in 1492 when Christopher

Columbus sailed there from Spain.

After Columbus’ voyage, many other

explorers and settlers came from

Europe. The Native Americans suffered.

Some died from diseases carried by the

Europeans. Others died fighting the

Europeans.

Colonies

The first lasting European settlement in

what is now the United States was Saint

Augustine, Florida. It was built by the

Spanish in 1565. The Spanish made

Florida and what is now the southwestern

United States into colonies. The

The United States is often called a melting

pot because it is made up of people of

many different cultures.

A large pipe carries petroleum

across the U.S. state of Alaska.

BRITANNICA STUDENT ENCYCLOPEDIA United States 27

English, the French, and the Dutch

(people from the Netherlands) also set

up colonies.

The English founded their first lasting

settlement in North America in 1607. It

was Jamestown, in what was later the

state of Virginia. Then the English built

other settlements and seized colonies

from the Dutch. Soon there were 13

English colonies along the Atlantic

coast.

In 1700 about 250,000 people lived in

the 13 colonies. By 1760 the population

was nearly 1.7 million. Many of the

newcomers were Africans who were

brought to work as slaves, especially in

the South.

American Revolution

In the 1760s the British government

started to tighten its control over the

colonies. Parliament, the British legislature,

forced the colonists to pay new

taxes. The colonists protested. Tension

built up between Britain and the colonies.

In 1775 fighting broke out between

colonists and British forces in Concord

and Lexington, Massachusetts. These

battles began the American Revolution.

On July 4, 1776, the colonies approved

the Declaration of Independence. This

document made the colonies into the

United States.

The American Revolution continued

until the British surrendered in 1781. By

signing a treaty in 1783, Britain

accepted the independence of the

United States.

The New Country

In 1787 representatives from the states

met in Philadelphia, Pennsylvania. The

meeting produced a document that outlined

a new government. The document

was the U.S. Constitution. It took effect

September 11,

1607 1776 1803 1861 1941 1973 2001

The English

set up their

first lasting

American

colony.

The American

colonies

declare their

independence

from Great

Britain.

The American

Civil War

begins.

Japan attacks

Pearl Harbor,

Hawaii, and

the United

States enters

World War II.

The last U.S.

troops fighting

in the Vietnam

War leave

Vietnam.

Terrorists carry

out attacks in

New York City

and near

Washington, D.C.

T I M E L I N E

The United States

nearly doubles its

size by buying

the Louisiana

Territory from

France.

28 United States BRITANNICA STUDENT ENCYCLOPEDIA

in 1789. GeorgeWashington became

the country’s first president.

The United States soon began to grow.

In 1803 President Thomas Jefferson

bought the Louisiana Territory from

France. The purchase added a vast area

west of the Mississippi River to the

United States. In 1819 the United States

acquired Florida from Spain.

Texas became a state in 1845. The

United States and Mexico disagreed over

the border between Texas and Mexico.

In 1846 the countries went to war. The

MexicanWar lasted until 1848. The

United States defeated Mexico and took

over California and the rest of the

Southwest.

CivilWar and Reconstruction

In the middle of the 1800s slavery

divided the United States. Southern

farms depended on slave labor, but

many Northerners were strongly against

slavery. In 1860 Abraham Lincoln was

elected president. His party, the Republicans,

opposed slavery. After Lincoln’s

election, the Southern states began to

secede (withdraw) from the United

States. They formed their own government.

It was called the Confederate

States of America, or the Confederacy.

In 1861 war broke out between the

U.S. government, called the Union,

and the Confederacy. This was the

American Civil War. The Confederacy

won most of the early battles, but by

1864 the Union was winning. In 1865

the Confederate general Robert E. Lee

surrendered.

The period after the CivilWar is known

as Reconstruction. The Republican leaders

of Congress passed harsh laws to

punish the South. These laws angered

many Southern whites. And even

though the war had ended slavery, African

Americans still struggled. Many

became poor farmworkers.

Growth of the Country

In the late 1800s the population of the

United States grew as more people

arrived from Europe. Many of them

settled in cities and took jobs in factories.

In the 1880s and 1890s industrial

production more than doubled.

As Eastern cities grew, more people

moved west. In a series of wars, settlers

and the U.S. Army forced Native

Americans to move onto reservations.

The final defeat of the Native Americans

came in the battle ofWounded Knee in

South Dakota in 1890.

In 1987 the United States celebrated the

200th anniversary of the creation of the

U.S. Constitution. As part of the

celebration a group of men dressed as

soldiers from the 1700s and carried flags

of that time period.

BRITANNICA STUDENT ENCYCLOPEDIA United States 29

By the end of the 1800s the reach of the

United States extended to faraway territories.

The United States bought Alaska

in 1867 and claimed Hawaii in 1898.

Also in 1898 the United States defeated

Spain in the Spanish-AmericanWar.

The United States took over Spain’s

colonies of Puerto Rico, Guam, and the

Philippines. The United States was then

a world power.

WorldWars and the Depression

In 1914 WorldWar I broke out in

Europe. The United States entered the

war in 1917. The American side, called

the Allies, won the war in 1918.

During the 1920s the United States

enjoyed peace and economic good

times. But in 1929 a “crash” in the stock

market started a serious economic

downturn called the Great Depression.

Many people lost their jobs and their

savings. In the 1930s President Franklin

D. Roosevelt started programs that

helped businesses and farmers and gave

people jobs. The programs were called

the New Deal. By 1940 the United

States was coming out of the Depression.

The next big challenge was WorldWar

II, which began in 1939 in Europe. The

countries of Germany, Italy, and Japan

were called the Axis powers. The other

side included Britain, France, and the

Soviet Union. They were called the

Allies. On December 7, 1941, Japanese

planes bombed a U.S. naval base at Pearl

Harbor, Hawaii. Then the United States

entered the war on the side of the Allies.

Presidents of the United States

Name Political Party* Term

George Washington — 1789–97

John Adams Federalist 1797–1801

Thomas Jefferson Democratic-Republican 1801–09

James Madison Democratic-Republican 1809–17

James Monroe Democratic-Republican 1817–25

John Quincy Adams National Republican 1825–29

Andrew Jackson Democratic 1829–37

Martin Van Buren Democratic 1837–41

William Henry Harrison Whig 1841

John Tyler Whig 1841–45

James K. Polk Democratic 1845–49

Zachary Taylor Whig 1849–50

Millard Fillmore Whig 1850–53

Franklin Pierce Democratic 1853–57

James Buchanan Democratic 1857–61

Abraham Lincoln Republican 1861–65

Andrew Johnson Democratic (Union) 1865–69

Ulysses S. Grant Republican 1869–77

Rutherford B. Hayes Republican 1877–81

James A. Garfield Republican 1881

Chester Arthur Republican 1881–85

Grover Cleveland Democratic 1885–89

Benjamin Harrison Republican 1889–93

Grover Cleveland Democratic 1893–97

William McKinley Republican 1897–1901

Theodore Roosevelt Republican 1901–09

William Howard Taft Republican 1909–13

Woodrow Wilson Democratic 1913–21

Warren G. Harding Republican 1921–23

Calvin Coolidge Republican 1923–29

Herbert Hoover Republican 1929–33

Franklin D. Roosevelt Democratic 1933–45

Harry S. Truman Democratic 1945–53

Dwight D. Eisenhower Republican 1953–61

John F. Kennedy Democratic 1961–63

Lyndon B. Johnson Democratic 1963–69

Richard M. Nixon Republican 1969–74

Gerald R. Ford Republican 1974–77

Jimmy Carter Democratic 1977–81

Ronald Reagan Republican 1981–89

George Bush Republican 1989–93

Bill Clinton Democratic 1993–2001

George W. Bush Republican 2001–09

Barack Obama Democratic 2009–

*Starting with John Adams, U.S. presidents have been elected as members of a

particular political party.

30 United States BRITANNICA STUDENT ENCYCLOPEDIA

U.S. forces fought in Europe and North

Africa and on islands in the Pacific

Ocean. The war in Europe ended in

May 1945, when Germany surrendered.

The war in the Pacific ended in August

1945, after the United States dropped

nuclear bombs on the Japanese cities of

Hiroshima and Nagasaki.

The ColdWar

AfterWorldWar II the United States

became involved in a tense rivalry with

the Soviet Union. The Soviet Union had

a Communist government. The United

States wanted to keep Communism

from spreading to other countries. This

rivalry became known as the ColdWar.

The first major conflict over Communism

was the KoreanWar. In 1950

Communist troops from North Korea

invaded South Korea. U.S. forces helped

South Korea fight the Communists. The

fighting lasted until 1953.

The VietnamWar was another fight

over Communism. Starting in the 1950s

Communist rebels tried to overthrow

the government of South Vietnam. The

United States helped South Vietnam.

Many people protested against the war.

U.S. troops gradually left Vietnam in

the early 1970s.

Civil Rights

In the 1950s and 1960s African Americans

struggled to gain better treatment.

Their efforts became known as the civil

rights movement. A minister named

Martin Luther King, Jr., led nonviolent

protests against segregation, or separation.

The Civil Rights Act of 1964

finally guaranteed many rights to African

Americans.

After the ColdWar

Relations between the United States and

the Soviet Union improved in the

1980s. In 1991 the Soviet Union broke

up, ending the ColdWar.

In the early 21st century the United

States worried more about threats from

terrorists than from other countries. In

2001 members of a terrorist group called

al-Qaeda hijacked (seized) four airplanes

and crashed three into buildings. The

attacks killed nearly 3,000 people.

After the attacks President GeorgeW.

Bush announced a “war on terror.” The

United States attacked Afghanistan in

2001 and Iraq in 2003. Bush accused

the leaders of both countries of supporting

terrorism.

In 2008 the United States elected its

first African American president. The

new president, Barack Obama, faced

many difficulties. They included the

ongoing wars in Iraq and Afghanistan

and a troubled economy at home.

..More to explore

American CivilWar • American

Revolution • Americas, Exploration and

Settlement of the • Confederate States of

America • Great Depression • Korean

War • Louisiana Purchase • Native

Americans • Reconstruction • Spanish-

AmericanWar • United States

Constitution • VietnamWar

•Washington, D.C.

BRITANNICA STUDENT ENCYCLOPEDIA United States 31

United States

Constitution

The United States Constitution is the

most basic law of the United States. All

other laws—including local, state, and

U.S. laws—must agree with the U.S.

Constitution.

History

No other country has a written

constitution that is older than the U.S.

Constitution.However, the Constitution

was a replacement for an even older set of

rules called the Articles of Confederation.

The articles were written when the

United States first became a country.

But there were problems with the

articles. In 1787 people met in Philadelphia,

Pennsylvania, to change them.

They soon wrote a completely new

document—the Constitution. Alexander

Hamilton and others then wrote essays

known as the Federalist papers to

explain the new Constitution.

During this time, the United States had

13 states. The Constitution went into

effect on March 4, 1789, after nine

states had approved it. All 13 states

approved it by 1790.

Federal System

The Constitution gave the United States

a federal system. In a federal system different

levels of government share power.

In the United States the national, or

federal, government shares power with

the governments of the states. Even so,

the national government gained more

power under the new Constitution than

it had had under the Articles of Confederation.

Separation of Powers

The writers of the Constitution also

wanted U.S. government leaders to share

power with each other. So they separated

the government into three equal

branches—legislative, executive, and

judicial.

Checks and Balances

Each branch has some power over the

others. This is called a system of checks

and balances. For example, the leader of

the executive branch (the president) gets

to appoint, or choose, many government

leaders. But part of the legislative branch

(the Senate) has the power to reject the

president’s choices.

Amendments

The Constitution can be changed.

Changes are called amendments.

Amending the Constitution is hard to

do. Two thirds of each house of Con-

A painting shows members of the Constitutional

Convention signing the United States

Constitution in 1787.

32 United States Constitution BRITANNICA STUDENT ENCYCLOPEDIA

gress and three fourths of the states must

approve every amendment.

The first 10 amendments went into

effect in 1791, only two years after the

Constitution became official. Those

amendments are called the Bill of

Rights. Only 17 other amendments have

been added to the Constitution since

1791.

#More to explore

Amendment • Articles of Confederation

• Bill of Rights • Federalist Papers

United States

Government

The United States government gets its

powers from the United States Constitution.

The Constitution organized the

government into three equal branches—

legislative, executive, and judicial.

Legislative Branch

The legislative branch of a government

holds the power to make laws. In the

United States, Congress is the legislative

branch. Congress also has the power to

declare war. A few legislative agencies,

like the Library of Congress, help Congress

in its work.

Members of Congress

Congress consists of two groups called

houses. One house is the Senate. There

are 100 senators, two from each state.

The other house is the House of Representatives,

or House. There are 435 representatives

in the House. The number

of representatives from each state is

based on the state’s population. States

with large populations have more representatives

than states with small populations.

Senators serve six-year terms. All voters

in a state elect both senators from that

state. States that have more than one

representative, however, are divided into

districts. People vote only for the representative

from the district in which they

live. Representatives serve two-year

terms.

Both houses of Congress have leaders.

The House leader is called the speaker

of the House. The political party that

has the most members in the House—

called the majority party—chooses the

speaker. The Senate leader is called the

president of the Senate. The vice

president of the United States serves as

president of the Senate but votes only

to break a tie. A senator called the

president pro tempore leads the Senate

U.S. senators and representatives gather in

the chamber, or meeting room, of the House

of Representatives to hear a foreign leader

speak.

BRITANNICA STUDENT ENCYCLOPEDIA United States Government 33

when the vice president is absent. The

majority party in the Senate chooses the

president pro tempore.

How Congress Makes Laws

A new law starts out as a document

called a bill. First a member of the

House or the Senate introduces a bill.

Then it goes to a small group of

representatives or senators called a

committee. There are many

committees. Committees have the

power to make changes in bills. They

also decide which bills the whole House

or Senate will vote on.

Once the bill is ready, the House or the

Senate votes on it. If more than half of

the members who vote on a bill approve

it, the bill passes, or gets approved. It

then goes to the other house for

approval. In order to become a law, a bill

must be passed by both houses.

A bill passed by both houses goes to the

president of the United States. If the

president signs the bill, it becomes a law.

However, the president can veto, or

reject, a bill. A vetoed bill can still

become a law, however. This happens if

two thirds of both houses of Congress

vote to override, or undo, the veto.

Executive Branch

The executive branch puts into use the

laws that the legislative branch makes.

The president of the United States leads

the executive branch.

The President

Presidents serve four-year terms. Since

1951 presidents have been limited to

two terms. The vice president takes over

if the president dies, gives up the job, or

is unable to serve.

A group called the electoral college elects

the president and the vice president

every four years. Voters in a national

election tell the electoral college members

from their state how to vote.

Congress can accuse the president of

breaking the law. This is called

impeachment. The Senate decides

whether the president is guilty. A guilty

president must resign, or step down.

Congress has impeached two

presidents—Andrew Johnson and Bill

Clinton—but the Senate found them

both not guilty.

Executive Power

The president decides what the

government should do. This is called

making policy. A part of making policy

is recommending laws for Congress to

pass. Another part is dealing with

foreign countries. As commander in

A member of

Congress

introduces a

bill by dropping

it into a

box called the

hopper.

The Oval Office in the White House is the

workplace of the president of the United

States.

34 United States Government BRITANNICA STUDENT ENCYCLOPEDIA

chief of the armed forces, the president

can send soldiers into battle in foreign

countries. However, only Congress may

declare war.

The president also oversees the departments

and government agencies that are

part of the executive branch. These

groups carry out laws and policies of all

kinds.

After the Department of Homeland

Security was created in 2002, there were

15 departments in all. The president

appoints their leaders. The leaders form

a group that is called the Cabinet. The

Cabinet gives advice to the President.

Judicial Branch

The judicial branch, or judiciary, is a

system of courts. Officials called judges

run the courts. The courts use the U.S.

Constitution and other laws of the U.S.

government to settle cases.

The president of the United States

appoints all federal judges, but the Senate

must approve them. Once approved,

the judges serve until death or retirement.

Federal judges, like presidents,

can be impeached.

Lower Courts

The district courts are the lowest level of

U.S. courts. District court trials usually

Executive Departments

Department Important Duties

Department of Agriculture Helps farmers; works to improve farming

Department of Commerce Works to protect businesses; carries out census

Department of Defense Oversees the armed forces

Department of Education Works to improve education

Department of Energy Manages the use of energy, including

nuclear energy and fossil fuels

Department of Health and Oversees social security programs;

Human Services ensures that food and drugs are safe

Department of Homeland Security Works to prevent terrorism in the United States and

protect national borders

Department of Housing and Works to improve housing and public areas of cities

Urban Development

Department of the Interior Oversees national parks and Native American affairs

Department of Justice Fights crime; oversees national prisons

Department of Labor Carries out laws that protect workers

Department of State Deals with foreign countries; protects U.S. citizens

outside the United States

Department of Transportation Works to keep highway, railroad, and airplane travel

safe and well organized

Department of the Treasury Collects taxes; pays the government’s bills; prints money

Department of Veterans Affairs Helps veterans (people who have served in the

U.S. armed forces)

Note: The heads of these departments belong to the president’s Cabinet.

Source: The White House (http://www.whitehouse.gov)

The president of the United States oversees the 15 departments of the executive branch.

BRITANNICA STUDENT ENCYCLOPEDIA United States Government 35

feature a jury and witnesses. A person

who loses a case in a district court can

appeal, or challenge, the decision in a

circuit court of appeals. Panels, or

groups, of judges usually hear cases in

courts of appeals. They have the power

to overturn, or undo, the judgments of

the lower courts.

Supreme Court

The Supreme Court is the highest court

in the United States. The nine judges on

the Supreme Court are called justices.

One is the chief justice. The others are

associate justices.

Most of the cases that the Court hears

are appeals of cases that lower courts

have already decided. The justices vote

on which cases they will hear.

When the Court hears a case, lawyers for

both sides get a chance to speak. But

there are no witnesses, and there is no

jury. After hearing the case, the justices

meet in private to make a decision. A

majority of the justices must agree

before the Court can make its decision.

One justice writes a statement called an

opinion to explain the decision. Justices

who disagree with the decision can write

their own opinions, which are called

dissenting opinions. Judges on lower

courts often use Supreme Court opinions

to decide later cases.

A Supreme Court decision may be

reversed by amending, or changing, the

Constitution. The Court also may

reverse one of its own decisions in a later

case. For example, in 1896 it allowed

segregation (forced separation of blacks

and whites) in public places. Then in

1954, in the case of Brown vs. Board of

Education of Topeka, the Court ruled

that segregation of public schools was

illegal.

Judicial Review

The Supreme Court has the power to

overturn a U.S. law or a state law that

does not follow the U.S. Constitution.

John G. Roberts, Jr., appears before a U.S.

Senate committee. Roberts was the president’s

choice to be chief justice of the United

States, or chief judge of the Supreme Court.

But he could not start work until the Senate

had approved him. Each branch of government

has some power over the other two.

The nine members of the U.S. Supreme

Court are called justices. They wear robes

in their courtroom.

36 United States Government BRITANNICA STUDENT ENCYCLOPEDIA

The Court declares such laws to be

unconstitutional. This power, called

judicial review, is not mentioned in the

Constitution. The Court first used judicial

review in 1803, in a case called Marbury

vs. Madison.

#More to explore

Electoral College • Government • Law

• Political Party • United States

Constitution • Voting

Universe

The universe is everything that exists,

including objects and energy, throughout

time and space. Earth, the sun, and

the rest of the solar system are only a

very small part of the universe. The size

of the universe is difficult to imagine. It

is so large that light from very distant

objects in the universe must travel billions

of years before reaching Earth.

The universe is also called the cosmos.

Cosmology is the branch of science that

studies the universe as a whole.

Astronomy is another name for the

study of the universe.

The MilkyWay and Other

Galaxies

The sun is in a group of stars known as

the MilkyWay galaxy. A galaxy is a large

system of stars, gas, and dust. Until the

early 1900s scientists did not know for

certain that there were galaxies outside

the MilkyWay. By using powerful telescopes,

scientists now estimate that the

universe has billions of galaxies.

The MilkyWay galaxy alone contains

more than 100 billion stars. Some galaxies

are larger, and some are much

smaller. But even small galaxies contain

hundreds of millions of stars. Galaxies

have a variety of shapes. For example,

some galaxies have the shape of a pinwheel.

The Expanding Universe

Most scientists believe that the universe

began suddenly in an event called the

big bang. They estimate that this happened

between 10 and 15 billion years

ago. At first the universe was tightly

packed and hot. In the time since then it

has expanded and cooled off. Clouds of

matter have come together to form stars,

planets, and other objects in space.

Some scientists believe that the universe

may stop expanding and begin to

A picture taken from the Hubble Space Telescope

shows a galaxy called the Small

Magellanic Cloud. New stars are forming

from the galaxy’s hot gas and dust.

BRITANNICA STUDENT ENCYCLOPEDIA Universe 37

contract. But most scientists believe that

the universe will keep expanding forever.

#More to explore

Astronomy • Galaxy • Solar System

• Space Exploration

Ural Mountains

The Ural Mountains of Russia form the

traditional boundary between Europe

and Asia. The Urals are about 1,550

miles (2,500 kilometers) long. They

extend from the Kara Sea in the north to

the Ural River in the south. The highest

peak is Mount Narodnaya at 6,217 feet

(1,895 meters).

The northern slopes of the Urals are

mostly covered with forests. Common

trees include oak, linden, elm, fir, pine,

and spruce. Treeless land called tundra is

found in the far north, especially at high

elevations. Arctic foxes, reindeer, brown

bears, lynx, wolverines, and elk are

among the animals of the range.

The economy of the Urals depends on

mineral supplies. Mountain mines produce

iron ore, copper, chromite, gold,

silver, and platinum. Factories make

metal goods, chemicals, and machinery.

The huge forests of the Urals provide

valuable wood. Farmers in the south

grow wheat, buckwheat, millet, potatoes,

and vegetables.

Russians entered the northern Urals in

the late 1000s. However, they did not

discover the range’s mineral riches until

the 1600s. In the 1700s the Urals

became one of Russia’s most important

industrial areas.

#More to explore

Russia

Uranus

Uranus was the first planet to be discovered

after the invention of the telescope.

It is the seventh planet from the sun. It

travels around the sun at an average dis-

The Belaya River runs through the southern

part of Russia’s Ural Mountains.

38 Ural Mountains BRITANNICA STUDENT ENCYCLOPEDIA

tance of about 1.8 billion miles (2.9

billion kilometers).

Physical Features

Uranus is the third largest planet in the

solar system. Its diameter, or distance

through its center, is about 32,000 miles

(51,000 kilometers). That is about four

times the diameter of Earth. Uranus is

most similar in size to Neptune, its outer

neighbor.

Uranus is one of the planets that are

called gas giants. It is made up mostly of

gases, mainly hydrogen and helium.

Small amounts of the gas methane give

the planet a blue-green color. Uranus has

no solid surface. Underneath its huge

layers of gases, it has a smaller area of

thick, hot liquid.

Narrow rings surround Uranus. These

rings seem very unlike the bright, icy

rings of the planet Saturn. The rings that

surround Uranus are made of some

unusually dark material.

Orbit and Spin

Like all planets, Uranus has two types of

motion: orbit and spin. Uranus orbits,

or travels around, the sun. It takes about

84 Earth years to complete one orbit. In

other words, a year on Uranus equals

about 84 Earth years.

Uranus spins about its center in an

unusual way. It is tilted so that it spins

nearly on its side. Also, Uranus is one of

the few planets in the solar system to

spin in a clockwise direction. Uranus

completes one rotation in about 17

hours, so a day on Uranus lasts about 17

hours.

Moons

More than 25 moons orbit Uranus. Its

five major moons are Oberon, Titania,

Ariel, Umbriel, and Miranda. They seem

to be composed of ice and rock. Some of

them have deep valleys and many large

pits called craters.

Observation and Exploration

Uranus cannot be seen from Earth without

the use of a telescope. The astronomer

William Herschel discovered

Uranus using his telescope in 1781. Uranus’

rings were discovered in 1977.

Only one spacecraft has visited the distant

planet. The unmanned U.S. spacecraft

Voyager 2 flew by Uranus in 1986.

#More to explore

Neptune • Planets • Solar System

• Space Exploration • Telescope

The spacecraft Voyager 2 photographed the

gassy planet Uranus in 1986. Experts

changed the colors in the image in order to

make the details easier to see.

Sometimes

storms occur

on Uranus.

However,

Uranus seems

to have fewer

storms than

the other gas

giants do.

BRITANNICA STUDENT ENCYCLOPEDIA Uranus 39

Urinary System

Humans need vitamins, minerals, and

other parts of foods and drinks in order

to live. As the body uses these things, it

creates substances that are not needed.

To stay healthy, the body must get rid

of these substances, called waste. The

digestive system forms solid waste from

food. Solid waste leaves the body

through the anus, at the end of the

large intestine. The urinary system

forms liquid waste, or urine, in the

kidneys. The bladder stores this urine

until it leaves the body through a tube

called the urethra.

Kidneys

In human beings and most other animals

the blood absorbs the wastes created

by the body. The blood carries these

wastes into two bean-shaped organs

called kidneys. The kidneys sit behind

the stomach on each side of the spine.

Kidneys do several things. They take

out any useful substances from the

blood and return them to the

bloodstream. They also take out liquid

wastes and extra water from the blood.

The kidneys then combine the wastes

and the water to make urine.

Bladder

Urine travels from each kidney down a

tube called a ureter. The two ureters lead

to the bladder. The bladder is a muscular

organ that expands like a balloon as

it fills with urine.

Urination

When the bladder is full, nerve endings

in the bladder send a message to the

brain. This message lets the person know

that the bladder needs to be emptied.

Blood containing waste enters a kidney. Within the kidney, tiny units called nephrons create

urine from waste and water in the blood. The blood then exits the kidney without the

waste. The urine leaves the kidney through a tube called the ureter.

40 Urinary System BRITANNICA STUDENT ENCYCLOPEDIA

Humans learn as children how to hold

in the urine by tightening nearby

muscles. When the muscles relax, urine

passes out of the bladder. It flows

through a tube called the urethra and

out of the body. This process is called

urination.

Problems with the Urinary

System

Like other parts of the body, the organs

of the urinary system may become

infected. This can make urination painful.

Several diseases can cause the kidneys

to stop working correctly.Wastes

then build up in the body and make the

person sick.

If the kidneys fail, doctors may use a

technique called dialysis to remove

wastes from the blood. In dialysis the

patient’s blood travels out of the body,

through a cleaning machine, and back

into the body. Doctors may also transplant

a healthy person’s kidney into the

patient.

Urinary Systems in Other

Animals

Like humans, most animals with a backbone

have kidneys and a bladder. However,

in birds, reptiles, and amphibians,

urine collects in a chamber called a

cloaca before leaving the body. Solid

waste also collects in the cloaca. Unlike

the watery urine of mammals and fish,

the urine of birds and reptiles is white

and thick. The urine of land insects is

solid.

#More to explore

Digestive System • Kidney

Humans and frogs both have kidneys and a

bladder in their urinary systems. Frogs and

other amphibians have a cloaca as well.

BRITANNICA STUDENT ENCYCLOPEDIA Urinary System 41

Uruguay

Uruguay is a small country on the east

coast of South America. Uruguay’s capital

is Montevideo.

Geography

Uruguay is the second smallest country

in South America, after Suriname. Uruguay

borders Brazil in the north and

Argentina in the west. To the southeast

is the Atlantic Ocean. To the south is a

part of the Atlantic called the Rio de la

Plata.

Hills and plains cover most of the land.

The Uruguay River runs along the border

with Argentina. The largest river

system in Uruguay is the Rio Negro. A

dam on this river created the Embalse

del Rio Negro, the largest lake in the

country.

Uruguay has mild winters and warm

summers. Rain is heaviest in the

autumn.

Plants and Animals

Tall prairie grasses cover most of Uruguay.

The country has few forests. Alder,

willow, eucalyptus, and poplar trees and

aloe plants grow near the rivers.

Some pumas and jaguars live in Uruguay.

Other native animals include

foxes, deer, wildcats, and large rodents

called capybaras. Caimans, which are

similar to alligators, live in the Uruguay

River. Uruguay’s birds include vultures,

parakeets, and flamingos.

People

Most Uruguayans have Spanish or Italian

ancestors. Mestizos, or people with

mixed European and American Indian

roots, form a small group. A smaller

number of people have African roots.

Almost all Uruguayans speak Spanish.

Roman Catholicism is the main religion.

Most people live in cities. Montevideo is

many times larger than Salto, the

second-largest city.

A gaucho (South American cowboy) herds

cattle in central Uruguay.

42 Uruguay BRITANNICA STUDENT ENCYCLOPEDIA

Economy

Most Uruguayans work in services,

including banking, communications,

and tourism. However, agriculture is

very important to the economy. Large

herds of cattle and sheep live on the

grasslands. The animals provide beef,

wool, leather, and dairy products.

Uruguay sells these products to other

countries. Farmers also grow rice,

wheat, corn, oranges, and sugarcane.

Fishing is another source of food.

Uruguay’s factories produce fuels,

chemicals, beverages, machinery, and

other goods.

History

A group of American Indians known as

the Charrua lived in the Uruguay region

hundreds of years ago. Spanish explorers

arrived in 1516, but they did not settle

the land.

Banda Oriental

The Spanish called the area the Banda

Oriental del Uruguay. The name means

“east bank of the Uruguay River.” Bands

of gauchos, or Spanish cowboys, hunted

the stray cattle that roamed through the

region. But the gauchos did not form

permanent settlements.

In 1680 the Portuguese set up a town in

the Banda Oriental. The Spanish

founded the city of Montevideo in 1726

and attacked the Portuguese. By the late

1770s the Spanish had driven out the

Portuguese.

In 1810 Spain’s American colonies

began fighting for independence. People

in the Banda Oriental defeated the

Spanish. However, Brazil soon took over

the Banda Oriental. After several years

of war the Banda Oriental finally won

independence in 1828. The new country

was called Uruguay.

Independence

Civil war erupted in Uruguay soon after

independence and continued for about

70 years. Uruguay became a stable

democracy in the early 1900s. In the

1960s a terrorist group called the

Tupamaros began trying to overthrow

the government.

The military took control of the government

in 1973. The military defeated the

Tupamaros, but it also ruled very

harshly. The military government jailed,

tortured, or killed many people who

disagreed with it. A democratic government

finally replaced the military leaders

in 1985.

..More to explore

Montevideo

The Punta del Este is a popular place for

vacations in southern Uruguay. Hotels line

the beaches along the Atlantic Ocean.

Facts About

URUGUAY

Population

(2008 estimate)

3,350,000

Area

68,037 sq mi

(176,215 sq km)

Capital

Montevideo

Form of

government

Republic

Major cities

Montevideo,

Salto, Paysandu,

Las Piedras,

Rivera

BRITANNICA STUDENT ENCYCLOPEDIA Uruguay 43

Utah

Each year on July 24, the U.S.

state of Utah celebrates Pioneer

Day. This holiday marks the day in

1847 when a group of Mormons seeking

religious freedom entered the Great Salt

Lake valley. These settlers worked hard

to build their community. Their hard

work is reflected in both the state’s nickname,

the Beehive State, and its motto,

“Industry.”

Today Mormons make up more than

half of Utah’s population. The Mormon

church still has a strong influence on life

in the state. Salt Lake City, the state

capital, is home to the world headquarters

of the Mormon church.

Geography

Utah is aWestern state. It is bordered on

the north by Idaho andWyoming, on

the east by Colorado, on the south by

Arizona, and on the west by Nevada.

Plateaus cover the southeastern part of

the state. This is an area of high mesas,

brightly colored canyons, and the Colorado

River.Western Utah is a broad, flat

area with deserts and some mountain

peaks. Located in this region are the

Great Salt Lake and the Great Salt Lake

Desert.

The northeastern part of the state is part

of the Rocky Mountains. TheWasatch

and the Uinta mountain ranges are in

this region. Utah’s climate is dry, with

warm summers and cold winters.

People

Utah is one of the nation’s most sparsely

populated states. In other words, very

few people are spread throughout Utah’s

very large countryside. More than 85

percent of the people are white and of

European heritage. Hispanic Americans,

the largest minority group, make up

about 9 percent of the population.

Economy

Service industries are the largest part of

Utah’s economy. They include health

care, engineering, telemarketing, and

computer-related services. Banking and

tourism are also important in the state.

More than 18 million tourists travel to

Utah each year. Among the items manu-

44 Utah BRITANNICA STUDENT ENCYCLOPEDIA

factured in Utah are transportation

equipment, metals, and processed foods.

Much of Utah’s farm income comes

from cattle and hogs. Utah’s primary

crop is hay.

History

Navajo, Ute, Shoshone, and Paiute Indians

lived in the Utah region before white

settlers arrived. Mexico claimed the

Utah area in 1821. Around this time

adventurers known as mountain men

arrived in the region to take part in the

fur trade. Trappers set up trading posts

in the area in the 1820s and 1830s.

After a war with Mexico, the United

States gained control of Utah in 1848.

The first group of Mormons entered

Utah in July 1847. In 1849 the colonists

formed the State of Deseret, with

Brigham Young as the first governor. A

year later the United States created Utah

Territory.

The Mormons applied for statehood six

times between 1849 and 1887. The federal

government, however, would not

allow Utah to become a state. The issue

preventing statehood was the Mormon

custom of polygamy (one husband having

several wives). In 1890 the Mormon

leadership banned polygamy, and in

1896 Utah became the nation’s 45th

state.

DuringWorldWar II Utah’s mining

industry increased to meet war needs. In

the 1960s the state became a center for

defense industries, both for research and

for manufacturing.

In the 1990s the population in Utah

increased by almost 30 percent. It continued

that growth in the following

decade, adding more than 20 percent to

its population by 2008. In 2002 Salt

Lake City hosted theWinter Olympic

games.

..More to explore

Mormon • Salt Lake City

The colorful formations of Bryce Canyon

National Park attract many visitors to Utah.

The Great Salt Lake is in the middle of a

very dry area in the U.S. state of Utah. Several

rivers feed into the lake. But because

the land is so dry, the water evaporates

quickly. The water that remains is very salty.

Where the water has dried up completely it

leaves behind salt crystals.

Facts About

UTAH

Flag

Population

(2000 census)

2,233,169—

rank, 34th state;

(2008 estimate)

2,736,424—

rank, 34th state

Capital

Salt Lake City

Area

84,899 sq mi

(219,887 sq

km)—rank, 13th

state

Statehood

January 4, 1896

Motto

Industry

State bird

California gull

State flower

Sego lily

BRITANNICA STUDENT ENCYCLOPEDIA Utah 45

Ute

The Ute are Native Americans of Colorado

and Utah. Their traditional homeland

also included parts of New Mexico.

The U.S. state of Utah was named after

the tribe.

The Ute built cone-shaped houses made

from poles covered with brush or grass.

The lands of the Ute were mostly very

dry. The only foods available there were

roots, seeds, lizards, insects, rodents, and

some other small animals. The Ute traveled

to the Rocky Mountains to hunt

larger animals and to fish. The Ute got

horses beginning in the 1600s. After

that they sometimes rode to the Great

Plains to hunt bison (buffalo).

Spanish traders began arriving in Ute

territory in the 1500s. The Ute traded

with the Spanish. They also sometimes

fought with them. In the 1840s U.S.

settlers began to arrive in the Ute lands.

By the end of the 1870s the U.S. government

had forced the Ute to give up

their territory. The tribe moved onto

reservations in Colorado and Utah. At

the end of the 20th century there were

more than 7,000 Ute living in the

United States.

#More to explore

Native Americans

Utopia

A utopia is an ideal, or perfect, place.

The word first appeared in a book written

by Sir Thomas More in the 1500s.

More came up with “utopia” by combining

Greek words meaning “no place.”

Some people have thought that though

no ideal community exists, people can

create one by working together.

In More’s book, Utopia is an imaginary

kingdom that is free from all cares, anxieties,

and miseries. Everyone lives in a

pleasant home surrounded by a garden.

More’s Utopia was not the first book of

its kind, and it was not the last. The

ancient Greeks wrote about utopias

more than 2,000 years ago. Utopian

books were especially common in the

1800s, when new scientific ideas made

people think about a better future. Utopias

became a common theme in science

fiction.

People have tried many times to establish

utopian communities. In North

America alone, more than 130 utopian

settlements were started between 1663

and 1858. Most failed.

#More to explore

Science Fiction

The Ute often carved pictures on rocks.

These carvings are known as petroglyphs.

46 Ute BRITANNICA STUDENT ENCYCLOPEDIA

Uzbekistan

Uzbekistan is a country in central Asia.

The capital is Tashkent.

Uzbekistan shares borders with Kazakhstan,

Kyrgyzstan, Tajikistan, Afghanistan,

and Turkmenistan. The only

mountains are in the far eastern part of

the country. The Aral Sea is in the

northwest. Uzbekistan has a dry climate

with hot summers and cool winters.

Uzbekistan has few forests. Grasses grow

in much of the country. Rodents, foxes,

wolves, and gazelles live in the west.

Boars, deer, bears, wolves, goats, and

lynx live in the mountains.

About three fourths of the people are

Uzbeks. There are also small groups of

Russians, Tajiks, and Kazaks. Islam is the

main religion.

Many of Uzbekistan’s people work in

agriculture. Uzbekistan is one of the

largest cotton growers in the world.

Other crops include wheat, vegetables,

and grapes. Farmers also raise cattle,

sheep, and goats. The land provides

natural gas, oil, gold, copper, and other

minerals.

In ancient times a trade route called the

Silk Road ran through the area. In the

700s Arabs brought in the religion of

Islam. Uzbeks came from the north in

the early 1500s.

The Uzbeks ruled until the 1800s, when

Russians took control. In 1924 the

Soviet Union made Uzbekistan one of

its republics, or states. Uzbekistan

gained independence in 1991.

..More to explore

Aral Sea • Tashkent • Union of Soviet

Socialist Republics

Ichan-Kala, or Royal Court, is a

historic area of Khiva, Uzbekistan.

It has many ancient buildings.

Facts About

UZBEKISTAN

Population

(2008 estimate)

27,345,000

Area

172,700 sq mi

(447,400 sq km)

Capital

Tashkent

Form of

government

Republic

Major cities

Tashkent, Namangan,

Samarkand,

Andijon,

Bukhara

BRITANNICA STUDENT ENCYCLOPEDIA Uzbekistan 47

The English scientist Edward

Jenner created the first vaccine,

a vaccine against smallpox, in

1796.

(See Vaccine.)

During his lifetime the Dutch

artist Vincent van Gogh sold

only one painting.

(See Van Gogh, Vincent.)

Vatican City, which is inside the

city of Rome, Italy, is the smallest

country in the world.

(See Vatican City.)

Queen Victoria was queen of

the United Kingdom from 1837

to 1901. She reigned over her

country longer than any other

British king or queen before

her.

(See Victoria, Queen.)

Fresh lava may be as hot as

2,200°F (1,200° C).

(See Volcano.)

V v

Vaccine

Vaccines are substances that prevent the

spread of disease. Giving people vaccines

can save millions of lives. For example,

smallpox killed some 2 million people in

1967. By 1979 the disease had disappeared.

This change resulted from a

worldwide program of vaccination.

How VaccinesWork

Many diseases are caused by tiny germs

called bacteria or viruses. When people

are vaccinated against a disease, they are

purposely given the bacteria or virus that

causes the disease. They can receive the

vaccine in a shot, by mouth, or by a

nose spray.

The bacteria or virus in a vaccine is dead

or weakened. It causes little if any sickness

in the person who receives it.

Instead it causes the body’s immune

system to make proteins called antibodies,

which fight disease. If the same bacteria

or virus enters the body later on,

the immune system will know how to

fight it off.

History

An English doctor named Edward Jenner

created the first vaccine in 1796. He

saw that people who got the mild disease

called cowpox rarely got smallpox,

which is more serious. He did experiments

to find out why. He scratched

material from a cowpox sore into the

skin of a healthy boy. The boy got cowpox.

Then Jenner scratched material

from a smallpox sore into the boy’s arm.

The boy stayed healthy. The cowpox

material was a vaccine against smallpox.

The French scientist Louis Pasteur was

another important researcher. In the

1880s he developed a vaccine against

rabies. He used a weakened form of the

rabies virus to protect against a full

attack by the same virus.

Since Pasteur’s time, scientists have produced

vaccines against many diseases. In

the middle of the 1900s Jonas Salk created

a vaccine that almost wiped out

polio. Vaccines have also been developed

for mumps, measles, cholera, plague,

tuberculosis, influenza, and hepatitis.

#More to explore

Disease, Human • Immune System

• Pasteur, Louis • Salk, Jonas

Vacuum

A vacuum is a space with nothing in

it—not even air. On Earth there is no

such thing as a total vacuum because it

is impossible to remove all the air from a

A child gets a shot containing a vaccine to

protect her against disease.

BRITANNICA STUDENT ENCYCLOPEDIA Vacuum 49

space. But partial vacuums are common.

A partial vacuum is a space with almost

no air inside.

Vacuums do not exist naturally on

Earth. Air surrounds everything on

Earth, and it extends for miles above

Earth. All of the air above Earth is pushing

down all the time. This is known as

air pressure. Because of the pressure, air

will try to fill any space. In outer space,

however, there is no air, so all of outer

space is a giant vacuum. That is why

astronauts must wear space suits. The

suits hold in air at the pressure that

humans are used to on Earth. Otherwise

their bodies would not function.

A partial vacuum can be made on Earth

by removing all solids and liquids and

then pumping air out of a container or

some other enclosed space. Vacuums

have many uses. A vacuum cleaner picks

up dirt by sucking air into a vacuum. A

medicine dropper creates a vacuum to

suck liquid into a tube. A vacuum

bottle, or Thermos, is a container with a

double wall. A vacuum between the

walls stops heat from flowing to or from

the outside air. This helps keep the liquid

inside cold or warm. Vacuums are

useful in industry, too. For example,

food companies use vacuum packaging

to help keep food from spoiling.

..More to explore

Air

Vaduz

Population

(2008 estimate)

5,110

Vaduz is the capital of Liechtenstein, a

country in central Europe. The town lies

in the Rhine River valley. It is Liechtenstein’s

cultural center. The castle of the

ruling prince of Liechtenstein overlooks

the town.

Tourism is important to the economy of

Vaduz. Small factories in the town make

high-technology equipment and other

products.

Vaduz dates back to at least the 1300s.

The town was destroyed in 1499 in a

war between Switzerland and the Holy

Roman Empire. Vaduz was rebuilt in the

early 1500s. It became a state within the

Holy Roman Empire.

In 1719 Vaduz was combined with a

state called Schellenberg to form Liechtenstein.

The Holy Roman Empire

Vacuum packing helps keep foods fresh. existed until 1806. Then Liechtenstein

50 Vaduz BRITANNICA STUDENT ENCYCLOPEDIA

became a German state. In 1866 it

became an independent country with

Vaduz as its capital.

#More to explore

Liechtenstein

Valentine’s Day

Valentine’s Day is a holiday that people

celebrate on February 14. It is also called

Saint Valentine’s Day. On Valentine’s

Day people greet loved ones, close

friends, family members, and school

classmates by sending them cards called

valentines. People also give candy, flowers,

and other gifts to loved ones. Valentine’s

Day gifts often come packed in a

red, heart-shaped box.

People have celebrated Valentine’s Day

with thoughts of love since at least the

1300s. According to an old European

legend, February 14 is the day when

birds pair off each year to start their new

families. February 14 is called Valentine’s

Day because the Roman Catholic

church honors two saints named Valentine

on that day. Both Saint Valentines

were ancient Romans of the AD 200s

who died for their Christian faith.

Groups of young men and women once

celebrated Valentine’s Day by picking up

valentines from a box. The person whose

valentine was picked up would become

the picker’s “valentine” for a year.

#More to explore

Festival and Holiday

Valhalla

In the tales of the Vikings and other

early people of Scandinavia, Valhalla was

a heaven for warriors. Scandinavia is a

region of northern Europe. Its tales are

known as Norse mythology.

According to the tales, Valhalla was a

vast banquet hall. It had at least 540

doors and a roof made of shields. The

powerful Norse god Odin ruled over

Valhalla. He allowed only warriors who

had died bravely to go there.

Female spirits called Valkyries watched

over battlefields. They brought dead

heroes to Valhalla. The warriors of Valhalla

ate the flesh of a boar (pig) that

was butchered every day and then magically

came back to life.

It was said that the dead warriors would

enjoy Valhalla until the end of the

world. Then they would rise again to

fight against evil giants and demons in a

final battle called Ragnarok.

#More to explore

Odin • Vikings

The prince of Liechtenstein lives in Vaduz

Castle in Vaduz, Liechtenstein.

The slain warriors

who lived

in Valhalla

were called

the Einherjar.

BRITANNICA STUDENT ENCYCLOPEDIA Valhalla 51

Valletta

Population

(2005

estimate), city,

6,300; urban

area, 81,050

Valletta is the capital of Malta, an island

country in the Mediterranean Sea. The

city is on the coast of the country’s largest

island, which is also named Malta.

Valletta lies on a piece of rocky land that

sticks out into a bay.

Trade and tourism are important to the

economy of Valletta. It is one of the

country’s main ports.

A group of Roman Catholic knights

founded Valletta in the 1560s. It became

the capital of Malta in 1570.

Great Britain took control of Malta in

the early 1800s. The British used Valletta

as a base for their Navy. During

WorldWar II (1939–45) the city was

bombed many times. Malta became an

independent country in 1964. Valletta

remained its capital.

..More to explore

Malta

Valley

A valley is a long depression, or ditch,

in Earth’s surface. It usually lies

between ranges of hills or mountains.

Most valleys are formed by rivers that

erode, or wear down, soil and rocks.

This process takes thousands or

millions of years.

River Valleys

Like other landforms, river valleys are

always changing. Rivers continually

wear away the land through which they

flow, gradually making the valleys

deeper. At the same time, other forces

loosen material on the valley walls.

These forces include rain, frost, and

wind. The eroded material from the

valley walls falls into the river and is

carried away.

Valleys are usually narrow when they are

first formed. Over time, however, most

valleys become wider as the walls are

worn away. One valley might grow

wider than another because the river

flows through a softer type of rock that

erodes more easily. The force of the river’s

flow also affects how a valley

changes over the years.