When the Soviets were looking for oil in 1971, the ceiling of an underground cave collapsed allowing natural gas to leak. The engineers decided to set fire to the gas and believed it would burn out in a couple of weeks. Instead, it has been burning for over 45 years.
Address Darvaza Fire Crater - Gate to Hell, Track to Darvaza Fire Crater, Turkmenistan
Coordinates 40°15'8.802" N 58°26'22.804" E