continent is one of Earth's seven main divisions of land. From largest to smallest, the continents are: Asia, Africa, North America, South America, Antarctica, Europe, and Australia.

Usually, all nearby islands are also considered to be part of a continent. Japan, for example, is part of the continent of Asia. Greenland and all the islands in the Caribbean Sea are usually considered part of North America, geographically. Only a very small number of islands are not considered parts of any continents.

Together, the continents add up to about 148 million square kilometers (57 million square miles) of land.

Continents are partly defined by culture. The continents of Europe and Asia, for example, are actually part of a single, enormous piece of land called Eurasia. However, because Asia and Europe are somewhat culturally distinct, most geographers treat them as two separate continents.

Continents Started To Form Four Billion Years Ago

The earth is made up of three main layers: the central core, the mantle, and the outer crust.

The crust and the top part of the mantle form a hard, stiff shell around Earth. This shell is broken up into huge sections called tectonic plates. These plates slide around on the molten mantle, which is so hot it remains in liquid form. Today, tectonic plates continue to slowly slide around the surface, just as they have been doing for hundreds of millions of years. Geologists believe this constant sliding helped form the continents.

The oldest known pieces of the continents began to form nearly four billion years ago, soon after Earth itself formed. At that time, a huge ocean covered Earth. Only a small fraction of the crust was made up of continental material. Scientists believe this material built up along the boundaries of tectonic plates due to something called subduction. During subduction, plates ram into each other, and the edge of one plate slides beneath the edge of another.

When heavy oceanic crust subducted toward the mantle, it melted in the mantle's enormous heat. Once melted, the rock became lighter and rose through the plate above and burst out as molten lava. When the lava cooled, it hardened into igneous rock.

Slowly, the igneous rock built up into small islands above the surface of the ocean. Over time, these islands grew bigger. When plates carrying islands subducted, the islands themselves did not descend into the mantle. Their material fused with that of islands on the neighboring plate. This made even larger landmasses, which over time became the first continents.

Scattered Chunks of Land

Millions of years ago, Earth looked very different as the continents were not where they are today. About 480 million years ago, most continents were scattered chunks of land lying along or south of the Equator. Millions of years of constant tectonic activity slowly changed their positions. By 240 million years ago, almost all of the world's land was joined in a single, huge continent that geologists call Pangaea.

About 200 million years ago, the supercontinent began to break apart. The pieces of Pangaea that began moving apart were the beginnings of the continents we know today.

A giant landmass that would become Europe, Asia, and North America separated from another mass that would split up into other continents. In time, Antarctica and Australia, which were still joined together, broke away and drifted south. The small piece of land that would become India also broke away, and for millions of years it moved north as a large island. It finally ran into Asia and slowly, the different landmasses moved to their present locations.

The positions of the continents are always changing. North America and Europe are moving away from each other by about 2.5 centimeters (one inch) a year. The continents are also continuing to break apart. In time, part of California will likely separate from North America and become an island.

Continental Features Take Shape

The surface of the continents has changed many times. The rocks that form the continents have been shaped and reshaped. Great mountain ranges have risen and then have been worn away. Ocean waters have flooded huge areas and then slowly dried up. Huge ice sheets have come and gone, shaping the land as they advance and then melt away.

On every continent, mountains continue to form. One way mountains form is through the crashing together of two tectonic plates, creating wrinkles in the crust, just as a rug wrinkles when you push against one end of it. These "wrinkles" are what we call mountains.

Asia's Himalayas were formed that way several million years ago. The plate carrying India slowly and forcefully shoved the landmass of India into Asia, which was riding on another plate. The collision of the two plates continues today, which, as a result, causes the Himalayas to grow taller every year.

North America

North America is the third-largest continent. It extends from the tiny Aleutian Islands in the northwest to the Isthmus of Panama in the south.

The West is full of young mountains, among them the Rockies, North America's largest chain. Older mountain ranges rise near the East Coast of the United States and Canada.

North America has a greater variety of climates than any other continent. It ranges from the freezing Arctic to the tropical jungles of Central America.

People sometimes mistakenly think the United States and Canada are the only countries in North America. In fact, Mexico, Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama are all also in North America. Greenland is also geographically part of North America, even though Denmark partly controls it.

South America

South America is connected to North America by the narrow Isthmus of Panama. The two continents weren't always connected, and only came together three million years ago.

South America is the fourth-largest continent. It extends from the sunny beaches of the Caribbean Sea to the icy waters near the Antarctic Circle.

The Andes is the longest mountain range on any continent and stretches the entire length of South America.

In northern South America, the Amazon River flows through the world's largest tropical rainforest. The Amazon is the largest river in the world.

South American rainforests contain an enormous wealth of animal and plant life. More than 15,000 kinds of plants and animals are found only in the Amazon River basin.

Twelve countries are located in South America.

Europe

Europe is the sixth-largest continent, containing just seven percent of the world's land. In total area, the continent of Europe is only slightly larger than the country of Canada. However, the population of Europe is more than twice that of South America. Europe has more than 40 countries and many of the world's major cities.

In the east, the Ural Mountains separate Europe from Asia. Two nations, Russia and Kazakhstan, are in both continents.

Europe's most famous mountain range is the Alps. It stretches from Albania to Austria, then across Switzerland and northern Italy into France.

Africa

Africa is the second-largest continent. It covers an area more than three times that of the United States. From north to south, Africa stretches about 8,000 kilometers (5,000 miles). It is connected to Asia by the Isthmus of Suez in Egypt.

The Sahara is the world's largest hot desert and covers much of North Africa. The world's longest river, the Nile, flows more than 6,560 kilometers (4,100 miles) from Lake Victoria to the Mediterranean Sea.

The top half of Africa is mostly dry, hot desert. The middle area has savannas, or flat, grassy plains. This region is home to wild animals such as lions, giraffes, and elephants. The central and southern areas of Africa are full of rainforests.

Africa also has mountainous areas. The peak of Mount Kilimanjaro in Tanzania is covered by snow all year long.

The continent of Africa is slowly splitting in two. In time, the land now containing the countries of Eritrea, Ethiopia, Djibout,i and Somalia will break off from the rest of the continent.

Africa is home to 56 countries, yet it accounts for only 14 percent of the world's total population.

Asia

Asia is the largest continent, and stretches from the eastern Mediterranean Sea to the western Pacific Ocean. Sixty percent of Earth's population lives in Asia. More than a third of the world's people live in China and India alone.

The continent of Asia includes many islands, some of them countries. The Philippines, Indonesia, Japan, and Taiwan are major island nations in Asia.

Altogether, there are more than 40 countries in Asia.

Asia has many different climate regions. They range from polar in the Siberian Arctic to tropical in equatorial Indonesia. Parts of central Asia, including the Gobi Desert, are dry year-round.

Asia is the most mountainous of all the continents. More than 50 of the highest peaks in the world are in Asia. Mount Everest, which is in both Nepal and China, is the highest point on Earth. It reaches more than 8,700 meters (29,000 feet) high in the Himalaya range.

Australia and Oceania

The name "Oceania" is a hint to this continent's defining characteristic: the Pacific Ocean.

Oceania is a region made up of thousands of islands throughout the Central Pacific and South Pacific. It includes Australia, which is the smallest continent in the world in terms of total land area.

Most of Australia and Oceania is in the Pacific. This vast body of water is larger than all the Earth's continental landmasses and islands combined.

Oceania is dominated by Australia. There are two other major landmasses of Oceania. One is the microcontinent of Zealandia, which includes the country of New Zealand. Much of Zealandia is formed by rocks that are underwater, with only New Zealand poking through the ocean surface.

The other large land area in Oceania is the island of New Guinea. It contains the country of Papua New Guinea; the rest of the island is ruled by Indonesia.

Oceania also includes three island regions: Melanesia, Micronesia, and Polynesia, which includes the U.S. state of Hawai'i. Australia and Oceania covers just less than 8.5 million square kilometers (about 3.5 million square miles). Australia and Oceania is the most lightly populated continent, with a population of fewer than 40 million humans. Most of the population lives in coastal cities.

Biologists who study animals consider Australia and Oceania a living laboratory. When the continent broke away from Antarctica more than 60 million years ago, it carried a cargo of animals with it. These animals developed into creatures found only in Australia, such as the koala, the platypus and the Tasmanian devil.

Antarctica

Antarctica is the windiest, driest, and iciest place on Earth. It is larger than Europe or Australia, but unlike those continents, it has no permanent human population. The only people living there are scientists.

The climate of Antarctica makes normal human life impossible. Temperatures plunge to lower than 73 degrees Celsius (100 degrees Farenheit) below zero. The continent is almost completely covered with ice. This ice layer is sometimes as thick as 3.2 kilometers (two miles deep).

Antarctica does not have any countries. 

 

Continent
This map beautifully illustrates the continent of Australia.
Noun

the art and science of cultivating land for growing crops (farming) or raising livestock (ranching).

ancient
Adjective

very old.

Antarctic Circle
Noun

line of latitude at 66.5 degrees south that encircles the continent of Antarctica.

arc
Noun

part of the outline of a circle.

Noun

layers of gases surrounding a planet or other celestial body.

barren
Adjective

unproductive.

Noun

a dip or depression in the surface of the land or ocean floor.

Noun

body of water partially surrounded by land, usually with a wide mouth to a larger body of water.

Noun

narrow strip of land that lies along a body of water.

blanket
Verb

to cover entirely.

Noun

deep, narrow valley with steep sides.

cargo
Noun

goods carried by a ship, plane, or other vehicle.

cattle
Noun

cows and oxen.

Central America
Noun

region that connects North America and South America, including the Isthmus of Panama.

Noun

complex way of life that developed as humans began to develop urban settlements.

climate
Noun

all weather conditions for a given location over a period of time.

coastal range
Noun

recently formed mountains found near the coast of continents, especially the western coasts of the Americas.

coastline
Noun

outer boundary of a shore.

colonize
Verb

to establish control of a foreign land and culture.

communication
Noun

sharing of information and ideas.

complex
Adjective

complicated.

conquest
Noun

victory.

Noun

one of the seven main land masses on Earth.

continental crust
Noun

thick layer of Earth that sits beneath continents.

Noun

part of a continent that extends underwater to the deep-ocean floor.

Noun

tiny ocean animal, some of which secrete calcium carbonate to form reefs.

coral reef
Noun

rocky ocean features made up of millions of coral skeletons.

Noun

the extremely hot center of Earth, another planet, or a star.

craton
Noun

old, stable part of continental crust, made up of shields and platforms.

Noun

rocky outermost layer of Earth or other planet.

crustacean
Noun

type of animal (an arthropod) with a hard shell and segmented body that usually lives in the water.

Noun

learned behavior of people, including their languages, belief systems, social structures, institutions, and material goods.

debris
Noun

remains of something broken or destroyed; waste, or garbage.

Noun

destruction or removal of forests and their undergrowth.

descend
Verb

to go from a higher to a lower place.

Noun

area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

development
Noun

construction or preparation of land for housing, industry, or agriculture.

distinct
Adjective

unique or identifiable.

dominate
Verb

to overpower or control.

drastic
Adjective

severe or extreme.

dust
Noun

microscopic particles of rocks or minerals drifting in space. Also called cosmic dust or space dust.

economic
Adjective

having to do with money.

Noun

community and interactions of living and nonliving things in an area.

Noun

height above or below sea level.

enormous
Adjective

very large.

Noun

imaginary line around the Earth, another planet, or star running east-west, 0 degrees latitude.

Noun

act in which earth is worn away, often by water, wind, or ice.

Eurasia
Noun

landmass including the continents of Europe and Asia.

evaporate
Verb

to change from a liquid to a gas or vapor.

evolution
Noun

change in heritable traits of a population over time.

exploration
Noun

study and investigation of unknown places, concepts, or issues.

explorer
Noun

person who studies unknown areas.

extensive
Adjective

very large.

farmland
Noun

area used for agriculture.

fertile
Adjective

able to produce crops or sustain agriculture.

Noun

region extending from the eastern Mediterranean coast through Southwest Asia to the Persian Gulf.

Noun

overflow of a body of water onto land.

Noun

material, usually of plant or animal origin, that living organisms use to obtain nutrients.

fragile
Noun

delicate or easily broken.

frequent
Adjective

often.

freshwater
Noun

water that is not salty.

frigid
Adjective

very cold.

fuse
Verb

to combine or meld together.

gas
Noun

state of matter with no fixed shape that will fill any container uniformly. Gas molecules are in constant, random motion.

geographer
Noun

person who studies places and the relationships between people and their environments.

geologic
Adjective

having to do with the physical formations of the Earth.

geologist
Noun

person who studies the physical formations of the Earth.

geology
Noun

study of the physical history of the Earth, its composition, its structure, and the processes that form and change it.

Noun

natural hot spring that sometimes erupts with water or steam.

giant sequoia
Noun

largest species of tree on Earth.

glacial period
Noun

time of long-term lowering of temperatures on Earth. Also known as an ice age.

Noun

mass of ice that moves slowly over land.

Noun

harvested seed of such grasses as wheat, oats, and rice.

gravity
Noun

physical force by which objects attract, or pull toward, each other.

grazing animal
Noun

animal that feeds on grasses, trees, and shrubs.

Great Lakes
Noun

largest freshwater bodies in the world, located in the United States and Canada. Lake Huron, Lake Ontario, Lake Michigan, Lake Erie, and Lake Superior make up the Great Lakes.

Great Plains
Noun

grassland region of North America, between the Rocky Mountains and the Mississippi River.

headwater
Noun

source of a river.

hominid
Noun

biological family of primates, including humans, chimpanzees, gorillas, and orangutans, and their ancestors.

Horn of Africa
Noun

large peninsula in northeast Africa, including the countries of Somalia, Djibouti, Eritrea, and Ethiopia. Also called the Somali Peninsula.

ice age
Noun

long period of cold climate where glaciers cover large parts of the Earth. The last ice age peaked about 20,000 years ago. Also called glacial age.

ice core
Noun

sample of ice taken to demonstrate changes in climate over many years.

Noun

thick layer of glacial ice that covers a large area of land.

Noun

rock formed by the cooling of magma or lava.

Indian subcontinent
Noun

landmass in south-central Asia carried by the Indian tectonic plate, including the peninsula of India.

indicate
Verb

to display or show.

Adjective

characteristic to or of a specific place.

industry
Noun

activity that produces goods and services.

iron
Noun

chemical element with the symbol Fe.

Noun

body of land surrounded by water.

isolate
Verb

to set one thing or organism apart from others.

Noun

narrow strip of land connecting two larger land masses.

jungle
Noun

tropical ecosystem filled with trees and underbrush.

laboratory
Noun

place where scientific experiments are performed. Also called a lab.

Noun

specific natural feature on the Earth's surface.

Noun

the geographic features of a region.

lava
Noun

molten rock, or magma, that erupts from volcanoes or fissures in the Earth's surface.

legacy
Noun

material, ideas, or history passed down or communicated by a person or community from the past.

linguistic
Adjective

having to do with language or speech.

Noun

molten, or partially melted, rock beneath the Earth's surface.

Noun

middle layer of the Earth, made of mostly solid rock.

medicine
Noun

substance used for treating illness or disease.

metal
Noun

category of elements that are usually solid and shiny at room temperature.

Noun

type of rock that has crashed into Earth from outside the atmosphere.

Noun

study of weather and atmosphere.

microcontinent
Noun

a type of large continental island.

Noun

clouds at ground-level, but with greater visibility than fog.

molten
Adjective

solid material turned to liquid by heat.

Noun

seasonal change in the direction of the prevailing winds of a region. Monsoon usually refers to the winds of the Indian Ocean and South Asia, which often bring heavy rains.

mountain
Noun

landmass that forms as tectonic plates interact with each other.

mountain range
Noun

series or chain of mountains that are close together.

Noun

art and science of determining an object's position, course, and distance traveled.

Nubian Plate
Noun

tectonic plate currently being formed in western Africa as the African Plate splits in two.

Noun

large body of salt water that covers most of the Earth.

Oceania
Noun

region including island groups in the South Pacific.

oceanic crust
Noun

thin layer of the Earth that sits beneath ocean basins.

orogeny
Noun

the way mountains are formed.

Outback
Noun

remote, sparsely populated interior region of Australia.

pack ice
Noun

large area of drift ice, or ice not attached to a shoreline.

Pampas
Noun

flat grasslands of South America.

Pangaea
Noun

supercontinent of all the Earth's landmass that existed about 250 million years ago.

Noun

piece of land jutting into a body of water.

permanent
Adjective

constant or lasting forever.

Noun

flat, smooth area at a low elevation.

Noun

large region that is higher than the surrounding area and relatively flat.

Noun

movement and interaction of the Earth's plates.

platform
Noun

ancient rocks that formed as part of continental crust, now overlain with sediment and sedimentary rock, located in the interior of continents.

polar
Adjective

having to do with the North and/or South Pole.

Polynesia
Noun

island group in the Pacific Ocean between New Zealand, Hawaii, and Easter Island.

precious
Adjective

very valuable.

primitive
Adjective

simple or crude.

Noun

area of tall, mostly evergreen trees and a high amount of rainfall.

Noun

areas of fast-flowing water in a river or stream that is making a slight descent.

Noun

any area on Earth with one or more common characteristics. Regions are the basic units of geography.

remnant
Noun

something that is left over.

remote
Adjective

distant or far away.

research
Noun

scientific observations and investigation into a subject, usually following the scientific method: observation, hypothesis, prediction, experimentation, analysis, and conclusion.

research station
Noun

structure or structures built for scientific study of the surrounding region, possibly including residential and lab facilities.

Noun

depression in the ground caused by the Earth's crust spreading apart.

rigid
Adjective

stiff.

river system
Noun

tributaries, mouth, source, delta, and flood plain of a river.

savanna
Noun

type of tropical grassland with scattered trees.

Noun

base level for measuring elevations. Sea level is determined by measurements taken over a 19-year cycle.

Noun

solid material transported and deposited by water, ice, and wind.

Noun

rock formed from fragments of other rocks or the remains of plants or animals.

shield
Noun

ancient rocks that formed as part of continental crust and are located in the interior of continents.

Siberia
Noun

region of land stretching across Russia from the Ural Mountains to the Pacific Ocean.

snow
Noun

precipitation made of ice crystals.

snowmelt
Noun

water supplied by snow.

soil
Noun

top layer of the Earth's surface where plants can grow.

Somali plate
Noun

tectonic plate currently being formed in eastern Africa as the African plate splits in two.

sparse
Adjective

scattered and few in number.

stable
Adjective

steady and reliable.

straddle
Verb

to be on both sides of an issue, area, or object.

subduct
Verb

to pull downward or beneath something.

subduction
Noun

process of one tectonic plate melting, sliding, or falling beneath another.

subduction zone
Noun

area where one tectonic plate slides under another.

summit
Verb

to reach the highest point of a mountain.

supercontinent
Noun

ancient, giant landmass that split apart to form all the continents we know today.

tectonic plate
Noun

massive slab of solid rock made up of Earth's lithosphere (crust and upper mantle). Also called lithospheric plate.

terrestrial
Adjective

having to do with the Earth or dry land.

theorize
Verb

to formulate and propose a group of ideas to explain a scientific question.

Noun

rise and fall of the ocean's waters, caused by the gravitational pull of the moon and sun.

Tierra del Fuego
Noun

group of islands at the southern tip of South America.

tourism
Noun

the industry (including food, hotels, and entertainment) of traveling for pleasure.

trade
Noun

buying, selling, or exchanging of goods and services.

tropical
Adjective

existing in the tropics, the latitudes between the Tropic of Cancer in the north and the Tropic of Capricorn in the south.

unique
Adjective

one of a kind.

valley
Noun

depression in the Earth between hills.

vast
Adjective

huge and spread out.

vegetation
Noun

all the plant life of a specific place.

volcanic island
Noun

land formed by a volcano rising from the ocean floor.

Noun

an opening in the Earth's crust, through which lava, ash, and gases erupt, and also the cone built by eruptions.

Noun

flow of water descending steeply over a cliff. Also called a cascade.

Noun

the breaking down or dissolving of the Earth's surface rocks and minerals.

wheat
Noun

most widely grown cereal in the world.