Turkmenistan's Darvaza Gas Crater, famously known as the "Door to Hell," has been burning for 54 years. This fiery spectacle, born from a 1971 Soviet drilling mishap, may soon extinguish naturally. While initially intended as a controlled burn to eliminate methane, the crater became a popular, albeit hazardous, tourist attraction.
source https://timesofindia.indiatimes.com/life-style/where-is-door-to-hell-located-on-earth-and-why-is-it-called-so/articleshow/123928171.cms
source https://timesofindia.indiatimes.com/life-style/where-is-door-to-hell-located-on-earth-and-why-is-it-called-so/articleshow/123928171.cms