Tallest pingo

The world's tallest pingo (aka hydrolaccolith) is Kadleroshilik Pingo (or Kadleroshilik Mound) located about 40 kilometres (25 miles) south-east of Prudhoe Bay in Alaska, USA. It rises to an elevation of 54 metres (178 feet) above the surrounding lake plain.

The second-tallest pingo (and the tallest in Canada) is the 49-m (161-ft) Ibyuk Pingo, in the Tuktoyaktuk Peninsula on the western Arctic coast of Canada; this region boasts the highest concentration of pingoes, with around 1,350 located on the peninsula.

Pingoes are ice-cored earth mounds found in permafrost-affected areas of the planet. They form via one of two processes - hydrostatically (closed-system) or hydraulically (open-system). Both involve groundwater freezing into a subterranean disc of ice and the resulting pressure/expansion causing the overlying soil above to bulge into a small hill.