A

David

Darling

pingo

A pingo is a cone-shaped mound that stands alone and has a core of ice. It is formed when freezing water expands and is forced upwards. Pingos are generally found in areas of permafrost, where water cannot reach the surface and therefore pushes up the ground it freezes. Pingos may be up to 90 m (330 ft) high and 800 m (2,600 ft) across.