Antarctica is the fifth largest continent on Earth, at over 5,400,000 square miles (14,000,000 sq. km), of which less than 110,000 square miles (280,000 sq. km) is free of ice — only about 2%. The continent lies primarily within the Antarctic circle, at the southernmost end of the Earth. Antarctica is consistently cold and dry — its low level of water in the air making much of the continent the largest desert on Earth.

Unlike most land masses on Earth, much of Antarctica has not been officially claimed by any nation. Instead, much of the continent is subject to what is called the Antarctic Treaty, with the terms of that treaty defining how the land can be used by various nations. In many ways, the territorial status of Antarctica is more closely related to that of the moon or outer space than of any terrestrial nation.

By treaty, Antarctica may be used only for peaceful purposes by any nation. No weapon testing may occur on the continent, and no military may serve a non-peaceful purpose there. The treaty also asserts that no nation may dispose of nuclear waste on Antarctica, that scientific exchange should occur, that no nation shall establish claim to the territory, and that nations shall have the right to freely observe anything on Antarctica. Later additions to the treaty protect wildlife on Antarctica, in keeping with the goal of protecting Antarctica as a zone of peace and scientific protection on Earth.

Some nations did in fact lay territorial claims to Antarctica, prior to the Antarctic Treaty in 1961. Argentina, France, Australia, Chile, Norway, New Zealand, and the United Kingdom all have existing territorial claims to small sections of Antarctica, dating from 1908 to 1943. Many of these territorial claims overlap, but for the most part the claims are superceded by the Antarctic treaty. Additionally, although the Antarctic treaty denies the right of any state to make future claims to territory in Antarctica, both the United States and the former Soviet Union have asserted their right to make such claims if they so choose.

Antarctica was a rumored continent for centuries before it was officially confirmed by Europeans. In some cases this belief was simply in a large southern landmass to balance the northern continents, in others it may have been based on early exploration. In 1820 a number of ships sighted mainland Antarctica from different positions. In 1821 an American sealing vessel landed on the main continent of Antarctica. Various places along the coast of Antarctica continued to be “discovered” for the next few decades. Exploration of the interior would take some time, however. In 1907 Shackleton’s arrived at the Magnetic South Pole, and in 1911 Amundsen arrived at the Geographic South Pole.

Various islands off the coast of Antarctica had temporary populations from the late 18th century on, but it was not until the 20th century that bases were set up on the mainland for scientific research. There are currently more than fifty research stations in Antarctica, housing between 1,000 and 4,000 people, depending on the season. The United States keeps the largest number of people in Antarctica, with around 1,400 during the summer season, followed by Chile and Argentina, with over 300 each.

In recent years, tourism to Antarctica has increased dramatically, with nearly 30,000 tourists a year visiting. These numbers continue to steadily increase, as tours become more common and the continent becomes portrayed more often in popular culture. Most Antarctic tours are for specific sightseeing experiences — such as going to see the Aurora Australis or a colony of penguins — but there are a number of more general tours offered as well.