'Door to hell' in desert hasn't stopped burning since fire in 1971

Turkmenistan is a former Soviet state on the border of Iran and at the edge of the Caspian Sea, with a population of about 5 million people.

More importantly, one of Turkmenistan's geographical features is the Karakum Desert, and it is one of the largest deposits of oil and gas in the world.

Any government would use these resources, and in 1971, the Soviet government was no exception.

However, when Soviet engineers drilled into the desert to extract the gas, the ground collapsed into a huge crater.

Nobody was hurt, but the engineers were afraid of poisonous gases escaping from the crater, and decided to burn it off.

They thought the gas would burn off in a matter of weeks, but the gas has been burning since that fateful day in 1971, turning the crater in the desert into the famous "Door to Hell."