A pingo is a mound of earth with a core of ice found in the Arctic and subarctic regions. Pingos are formed as a result of what is called a “closed” system of unfrozen soil developing within an area of permanently frozen ground.
Tuktoyaktuk in the Mackenzie Delta of the Northwest Territories in Canada has one of the highest concentrations of pingos, with some 1,350 examples. Aside from Canada, pingos occur in Greenland, Siberia, and the Norwegian island of Spitsbergen. Recent estimates indicate that more than 11,000 pingos exist on Earth, with more than 6,000 alone in northern Asia.