Greenland is the largest island in the world. Owing to its situation in the north, where the Atlantic meets the Arctic Ocean, Greenland is surrounded principally by cold ocean currents, so the coasts are constantly being cooled. This, together with the radiation of cold from inland ice, gives Greenland its Arctic climate. The ice-sheet or inland ice covers 1,833,900 km2 – equal to 85% of Greenland’s total area and extending 2,500 km north- south, and up to 1,000 km east-west. At the center, the ice is up to 3 km thick and represents 10% of the world’s total fresh water reserves. The ice-free area covers an expanse of 350,000 km2 – corresponding to the size of France. Approximately one third of Greenland is designated as national park. In 1974, 750,000 km2 of northeast Greenland was registered, forming the world’s largest national park. Greenland’s geological history is the oldest in the world. Greenland is the site of the oldest rocks ever dated: about 3.7 billion years old. By way of comparison, the earth is reckoned to be 4.6 billion years old. It has been demonstrated that 75% of Greenland’s subsoil, including the area beneath the inland ice, must be at least 1.6 billion years old. The glaciers of the ice age have shaped Greenland’s topology, but in several locations traces of geological processes have been found, such as earthquakes, formation of mountain ranges and volcanic activity. No wonder Greenland is an El Dorado for geology buffs.