The Darvaza gas crater also called the Gates of Hell or Door to Hell, is a natural gas field in Turkmenistan that collapsed into an underground cavern.
Soviet engineers set the 230-foot hole on fire while exploring for gas in 1971. They expected the flames to die after a few days, but the opening burned continuously. Geologists set the escaping methane on fire to avoid poisoning nearby villages.
The fiery gas crater in the Karakum Desert has been in flames for over 50 years and can be seen from miles away.