Antarctic pack ice

Penguins

Iceberg

There is eight times more ice in Antarctica than in the Arctic at the opposite end of the globe, and the southern continent has 70% of the world's fresh water locked within its frozen embrace. If Antarctica's ice cap melted, say some scientists, there would be a global rise in sea levels of 60m (200ft) and London would be flooded.

The largest recorded iceberg originating from Antarctica was bigger than Belgium.

Poles apart
The South Pole and the South Magnetic Pole are not the same thing.

The geographical South Pole - the one reached by Amundsen and Scott - is the southern end of the Earth's axis of rotation. Imagine that the Earth is an orange and a skewer is stuck through it from top to bottom. As the skewer is twisted, so the orange rotates. The point where the skewer pierces the orange at the bottom is the equivalent of the South Pole.

The South Magnetic Pole is much harder to describe. It is the place from which the magnetic fields in the southern part of the globe appear to radiate. You would know that you have reached the South Magnetic Pole when the magnetic needle you are carrying dips vertically, rather than swinging from side to side. The position of the South Magnetic Pole has moved since the beginning of the 17th century in a general north-westerly direction, at a rate of about eight miles a year. It is currently located in the Southern Ocean off Adélie Land.

Wild weather
When taken as a whole, Antarctica is the highest, coldest and windiest of all the continents. The highest peak is the Vinson Massif at just over 4,900m (16,000ft), while the South Pole is 2,835m (9,300ft) above sea level. At the pole, there are six months of darkness and six months of daylight each year. The coldest temperature ever recorded anywhere on Earth was at Russia's Vostok base in the interior: in July 1983, thermometers plummeted to -89.2ºC (-128.6ºF). The warmest it has ever been at the South Pole is -14ºC (6.8ºF), but the mean Antarctic coastal temperature in summer reaches a dizzy 0ºC (32ºF). Annual precipitation (measured as melted snowfall) in the interior is less than 5 centimetres (2 inches) - similar to the Sahara desert. The katabatic winds (see 'Climate' inTravel tips) emanating from the interior can reach 185mph on the coast.

Antarctic treaty
The Antarctic Treaty, designed to keep the continent free for scientific study and to prohibit any military activity, was signed on 1 December 1959 by 12 nations: Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, the Soviet Union, the United Kingdom and the United States.

Since then, a further 14 countries have joined the original 12 as 'consultative parties', which means that 26 nations now have full voting rights at meetings concerning the treaty. Another 17 countries have also joined as 'non-consultative parties' with observer status at meetings. Any party to the treaty that shows a genuine interest in Antarctica by conducting scientific research activities is entitled to become a consultative party. All decisions are made by consensus - that is, all consultative parties must agree.

Seven signatory countries - Argentina, Australia, Chile, France, New Zealand, Norway and the UK - claim territorial rights to certain areas. Three claims even overlap - Argentina, Chile and the UK all reckon that the Antarctic peninsula belongs to them.

The treaty came into force in 1961. Given the mineral resources present on the continent, the treaty was chiefly a political ploy to prevent any one country grabbing more than its fair share.

Today, scientists from 28 countries are based in Antarctica. In 1991 (the first time the treaty came up for renewal), a Protocol on Environmental Protection was agreed in Madrid, designating the continent as a nature reserve and banning the commercial extraction of oil and minerals for 50 years.

Biggest base
The largest Antarctic station is the American McMurdo site on Ross Island in the Ross Sea. Established in 1956, it now numbers more than 100 buildings, including a sauna, a gym and a bowling alley, plus three airstrips. The summer population of about 1,000 drops to 150 in winter. Residents have even grown their own salad in a special greenhouse, using a solution rich in nutrients rather than soil. From 1962 to 1972, electricity came from a nuclear power plant.

Digging deep
By drilling out deep ice cores in Antarctica, researchers have access to 500,000 years of global climatic information as atmospheric gases and volcanic ash are trapped in the bubbles of ice. For example, they have been able to track the increase, in modern times, of carbon dioxide, a gas involved in global warming.

Lake Vostok is a huge buried lake that scientists are keen to probe for signs of ancient organisms that might have adapted to the hostile conditions found at the bottom of the world - a possible key to life on other planets. However, because the cost of exploration would run into millions of pounds, excavation of the lake has yet to begin.

Meteorite finds
Between 1969 and 1999, 20,000 meteorites were found in the Antarctic. When analysed, the make-up of one meteorite known as ALH84001, discovered in the Allan Hills in 1984, proved comparable to material from the Martian atmosphere chemically measured by the Viking landers eight years before. NASA scientists now believe that ALH84001 was catapulted from Mars when that planet was itself hit by a meteoroid, and it eventually found its way to Earth 13,000 years ago. Minuscule Martian microfossils were allegedly found within the meteorite, giving rise to speculation about 'life on Mars', although other boffins have since discounted the theory.

Little creatures
The largest insect in Antarctica is a wingless midge, Belgica antarctica, with a length of less than 1.3cm (0.5in). There are no flying insects, just shiny black springtails that hop like fleas and tend to live among penguin colonies.

Gondwanaland
Antarctica was originally part of the 'supercontinent' of Gondwanaland - which also included the future South America, Africa, India and Australasia - which began to break up during the Jurassic era 180 million years ago. At that time, Antarctica was much further north than it is today, and was covered with forests in which dinosaurs roamed. Then, as it began to drift south, it started to freeze over.

A scientific paper written in 1904 by A G Nathorst was the first to suggest that the continent once had a subtropical climate, but it wasn't until the 1960s that the scientific community took the supercontinent theory seriously.