The Batagaika crater in Batagay, Siberia, first appeared in the 1960s. Lying just within the Arctic Circle, scientists believe the crater was formed by melting permafrost turning the surface to slush. The crater, which is expanding by around 15m each year, is just one of a number of holes opening up as temperatures around the world rise.
Read more about this fascinating feature of the Siberian landscape in the following articles:
Photo: (Julian Murton/University of Sussex)