The "Door to Hell"
Derweze underground is rich in natural gas
. In 1971, during a drilling, geologists accidentally found an underground cavern filled with natural gas. The ground on which the drilling rig was placed collapsed, leaving a large gaping hole exposed with a diameter of about 50-100 meters. To avoid poisonous gases coming out of the hole, it was decided to let the gases burn. As of 2009
, gases in the underground cavern are still burning without interruption. Locals have named the cavern The Door to Hell