Longest burning methane crater

Near the village of Derweze, Turkmenistan, is a crater within the natural gas field that has been burning since 1971. Details on the origins of this feature are not completely known, but it is believed that the crater formed as the ground collapsed when drilling equipment drilled into an underground void. In order to prevent a large leak of methane gas into the environment, geologists set the crater on fire, believing that it would rapidly run out of fuel. The crater, known as the Derweze crater or the Davarza crater, is also nicknamed "The Door to Hell". It measures some 69 m across and 30 m deep, and has been burning ever since.

The first scientific expedition into the crater was led by George Kourounis in 2013.