The Door to Hell, a cavern generously filled with natural gas, was discovered in 1971 by Soviet geologists. This gas rich area is situated near the village of Derweze, Turkmenistan 40°15′10″N 58°26′22″E. While drilling, the ground beneath the rig collapsed, leaving a large hole with a diameter of 70 meters / 250 ft behind. Authorities decided to burn the gas to avoid toxic discharge. The gas is still burning today, even though geologists initially estimated that the fire would use all the fuel in a matter of days.