In Turkmenistan a pit has been burning for over 40 years.
In 1971, when the republic was still part of the Soviet Union, a group of Soviet geologists went to the Karakum in search of oil fields. They found what they thought to be a substantial oil field and began drilling. Unfortunately for the scientists, they were drilling on top of a cavernous pocket of natural gas which couldn't support the weight of their equipment. The site collapsed, taking their equipment along with it [...] Natural gas is composed mostly of methane, which, though not toxic, does displace oxygen [...] So the scientists decided to light the crater on fire, hoping that all the dangerous natural gas would burn away in a few weeks' time.
In 1971, when the republic was still part of the Soviet Union, a group of Soviet geologists went to the Karakum in search of oil fields. They found what they thought to be a substantial oil field and began drilling. Unfortunately for the scientists, they were drilling on top of a cavernous pocket of natural gas which couldn't support the weight of their equipment. The site collapsed, taking their equipment along with it [...] Natural gas is composed mostly of methane, which, though not toxic, does displace oxygen [...] So the scientists decided to light the crater on fire, hoping that all the dangerous natural gas would burn away in a few weeks' time.
https://www.smithsonianmag.com/travel/giant-hole-ground-has-...