Greenland is the largest island on Earth.

Most of Greenland, which lies east of Canada, is within the Arctic Circle.

Icecap and Glaciers

About one tenth of all the ice on Earth is contained within an icecap that covers about two thirds of Greenland

However, global warming may cause the amount of ice in the Greenland icecap to change.

Snow falls on the icecap throughout the year, sometimes in the form of steady falls and sometimes in the form of violent blizzards.

It is never warm enough for the snow to melt. As the snow builds up, it crushes the snow beneath it. The pressure turns the lower layers into ice.

The huge pressure caused by the accumulation of snow and ice squeezes out icecap's lower layers of ice, pushing them as glaciers through passes in Greenland's coastal ring of mountains.

When a glacier reaches the sea, it begins to melt. Cracks open up within the ice. As these widen, icebergs break off at the seaward edge and float away with the tides and currents.

Each spring and summer, thousands of icebergs drift southward from Greenland's west coast and head for the Grand Banks of Newfoundland and the shipping lanes of the North Atlantic.

Rocks

Beneath Greenland's ice lie some of the oldest rocks on Earth.

Scientists have dated samples of metamorphic rock from Nuuk, or Godthåb, the capital, to the early Precambrian Era, around 3,700 million years ago.

The same bedrock extends westward to form the core of Canada's landmass.

Jagged mountain peaks tower more than 2,600m (12,000ft) above a coastline deeply indented by fjords, while inland the ground slopes down to form a vast, saucer-shaped depression.

Greenland Life

In the north of Greenland, snow covers the tundra for most of the year. However, life blossoms during Greenland's brief summer.

For a few weeks each year, mosses, lichens and grasses carpet the ground, providing a staple diet for a large range of animals, such as reindeer.

In the winter, reindeer herds must dig through the snow for food. Sometimes, they must travel large distances to find new feeding grounds.

The muskox, which is related to the sheep, stands about 1.6m (5ft) high. It has a waterproof coat. The muskox eats continuously throughout the summer so that it can build up fat reserves that will enable it to survive the winter.

In the summer, dozens of bird species flock to Greenland's coastal regions of Greenland to feed on abundant vegetation.

The arctic tern has the longest regular migration route of any animal. During the northern winter, these birds fly halfway round the world to the Antarctic to take advantage of the southern summer, then return north to breed the following year.

Greenland's waters are full of shrimp. The waters of Disko Bay, off the western coast, contain some of the largest shrimp beds in the world.

The waters surrounding Greenland contain vast amounts of plankton, the microscopic plants and animals that are the base of most marine food chains.

The bowhead whale, which often visits Greenland's shores, can grow up to 15m (50ft) long, of which no less than 5m (16.5ft) is made up by the skull. It is probably the longest of all whales that filter-feed on plankton.

Plankton is food for an enormous amount of fish, including cod, salmon and halibut.

The fish are, themselves, food for seals. Thousands of seals, which flourish in the cold sea, may gather when it is mating season or when they are moving to new feeding grounds.

Large groups of walruses, which eat crabs and shellfish, also assemble in masses on Greenland's shores.