The North Pole lies not on land but in the ocean: the Arctic Ocean. It is permanently covered by ice, although the ice cover shrinks in the summer months as it melts. The South Pole lies on the continent of Antarctica. This huge, mountainous landmass is mostly covered by an ice sheet all year round.

The North Pole lies on a floating sheet of ice, 2–3 metres (6–10 feet) thick, formed by freezing of the seawater in the middle of the Arctic Ocean. In winter, pack ice forms around the edges of the ice sheet. These are slabs of ice that are constantly being broken up and crushed together by the movement of the water underneath. Greenland is mostly covered with ice throughout the year.

Antarctica

Nearly the whole continent of Antarctica is covered by ice all year round. In some parts, the ice is more than 3.5 kilometres (2.2 miles) deep. In winter, the waters of the Southern Ocean, which surrounds the continent, are covered with floating pack ice and icebergs.

Antarctica is the coldest, driest and windiest continent. It is actually a desert: it hardly ever rains or snows here. Antarctica is inhabited only by people who work at scientific research stations. The coldest temperature ever recorded on Earth was -89.2°C (-128.6°F) at the Russian Vostok Station in 1983.