Travel deep into Turkmenistan and, alongside the nomads and gold statues of an insane former leader, you'll stumble across a fire that's burned for so long that its nickname, 'The Door to Hell', is only slightly histrionic.
Located in the small village of Derweze, the flame pit sprung into horrible life when a drilling site collapsed in 1971 (creating the massive pit) and the Soviet scientists, in their wisdom, decided that the best way to stop the poisonous gasses escaping was to set the entire thing on fire. They calculated it would burn out in a day or two, and it turns out they were only off by a figure of 40 years and counting.
This side of the Cold War the pit is still burning strong, standing as a testament to both human stupidity, and, in its own Mordor-like way, the weird diversity of the planet.
Images: Rapid Travel