Top 10 Arctic facts

A fizz. When a piece of iceberg ice melts, it makes a fizzing sound called "Bergie Seltzer". This sound is made when the water-ice interface reaches compressed air bubbles trapped in the ice. As this happens, each bubble bursts, making a 'popping' sound. The bubbles contain air trapped in snow layers very early in the history of the ice, that eventually got buried to a given depth (up to several kilometers) and pressurized as it transformed into firn then to glacial ice.

The soil. The permafrost prevents trees from developing a deep root system. Climate variations or forest fires can thaw the upper extents of the permafrost, creating a ground slump called thermokarst.

Roald Amundsen. In a three year journey between 1903 and 1906, Amundsen explored the passage with a crew of no more than six, in the converted 47-ton herring boat Gjøa. Spending winters with ship trapped in ice, he learned from the local Netsilik people about Arctic survival skills that would later prove useful. For example, he learned to use sled dogs and to wear animal skins in lieu of heavy, woolen parkas. Amundsen later led the expeditions to discover the South Pole (1911) and the North Pole (1926).

Bear. The word Arctic comes from the Greek word arktos meaning bear and the adjective arktikos "of the bear". The name refers either to the constellation Ursa Major, the "Great Bear", which is prominent in the northern portion of the celestial sphere, or to the constellation Ursa Minor, the "Little Bear", which contains Polaris, the Pole star, also known as the North Star

In Iceland. All penguins are native to the Southern Hemisphere, but they are not found only in cold climates. Several species are found in the temperate zone of South Africa and South America. The Galápagos Penguin (pictured) lives near the equator. Fossils show that many prehistoric species lived in warm climates.

Approx 3700 m (12000 ft). Gunnbjørn Fjeld is Greenland's highest mountain. It is a nunatak, a rocky peak protruding through glacial ice. The mountain is named after Gunnbjorn Ulfsson, the Viking who was the first European to reach Greenland.

Neither east, west, nor south. At the South Pole every direction is north.

Sea otters. Alaska was colonized by Russian fur traders. Rather than hunting by themselves, the Russians forced the Aleuts to do the work for them. Many of Aleuts had been removed from their home islands and sent as far south as California to hunt sea otter.

Underground monster. The word mammoth comes from the mythology of the Siberian peoples who believed they lived underground - as dead ones were found in the ground from time to time.

They approach diving. A resting seal would try to escape to the sea when attacked (where it easily outswim a polar bear), so the attack from the sea is a very efficient hunting strategy. Polar bears are able to dive to a depth of 15 feet and remain submerged for up to two minutes.