In 1971, Soviet geologists discovered a site near to Derweze, Turkmenistan, that they believed harboured oil. Work drilling the area for its resources began soon after the area was acknowledged. However, all was not as it seemed beneath the surface when they failed to find oil. They quickly realised that they were sitting upon a giant gas crater, which collapsed shortly after work began. Fear spread that the gasses that were emitting from the crater were poisonous.
With this in mind, scientists took the slightly extravagant step of setting the crater on fire. This, they believed, would prevent the gasses from spreading, and then fire should burn out within a week. But, some 44 years later, the fire is still burning.
The Derweze crater has been named The Door To Hell. The 230ft wide pit was given the fitting name by local residents in the village of Derweze due to the searing heat it emits and the red glow that can be seen by the community, with a population of just 350, a few miles away.
Gozel Yazkulieva, a visitor from the Turkmenistan capital Ashgabat, told AFP in 2014: "It takes your breath away. You immediately think of your sins and feel like praying."
The area has become something of a tourist hotspot in recent years. It is estimated that The Door To Hell attracts between 12,000 and 15,000 visitors a year. However, in 2009, the president of Turkmenistan, Gurbanguly Berdimuhamedow, ordered that the hole be closed, but this has yet to come to fruition.
In 2013, explorer George Kourounis became the first person to step foot within the burning hole, which is 99ft deep, as he hoped to collect soil samples from the scorching soil in a bid to learn about whether life can survive in such harsh conditions. This would have helped scientists gain a better understanding of potential life on other planets that have similar conditions. Some bacteria was actually found living inside.
Describing his encounter with The Door To Hell, Kourounis told National Geographic: "When you first set eyes on the crater, it's like something out of a science-fiction film. You've got this vast, sprawling desert with almost nothing there, and then there's this gaping, burning pit... The heat coming off of it is scorching. The shimmer from the distortion of it warping the air around it is just amazing to watch, and when you're downwind, you get this blast of heat that is so intense that you can't even look straight into the wind.
"I described it as a coliseum of fire − just everywhere you look it's thousands of these small fires. The sound was like that of a jet engine, this roaring, high-pressure, gas-burning sound. And there was no smoke. It burns very cleanly, so there's nothing to obscure your view. You can just see every little lick of flame. There were a few moments that I just literally had to stop, look around, and drink in the spectacle of where I was."