#5: The Door to Hell (Turkmenistan)
You do not want to roast marshmallows over this fiery pit in the middle of the desert. It was while drilling for oil by Soviet engineers in 1971 that the ground caved in to this gigantic, gas-filled crater. To save the nearby villages from the risk of these gases, the scientists thought to burn the gases, and the fire should go out within 2 weeks.
