The Door To Hell, Turkmenistan ☺

 The "Door to Hell" or ''Gates of Hell" is a natural gas field in Derweze, Turkmenistan, that collapsed into an underground cavern, becoming a Natural Gas crater. 

The gas crater is located near the village of Derweze, also known as Darvaza.

 It is in the middle of the Karakum Desert, about 260 kilometres (160 mi) north of Ashgabat, the capital of Turkmenistan. 

The gas reserve found here is one of the largest in the World. 

The name "Door to Hell" was given to the field by the locals, referring to the fire, boiling mud, and orange flames in the large crater, which has a diameter of 70 metres (230 ft).

The hot spots range over an area with a width of 60 metres (200 ft) and to a depth of about 20 metres (66 ft).

The site was identified by Soviet Scientists in 1971. It was thought to be a substantial oil field site. 

The scientists set up a drilling rig and camp nearby, and started drilling operations to assess the quantity of gas reserve available at the site. 

As the Soviets were pleased with the success of finding the gas resources, they started storing the gas. 

The ground beneath the drilling rig and camp collapsed into a wide crater and disappeared. 

No lives were lost in the incident. 

However, large quantities of methane gas were released, creating an Environmental problem and posing a Potential danger to the people of the nearby villages. 

Fearing the release of further poisonous gases from the cavern, the scientists decided to burn it off. 

They thought that it would be safer to burn it than to extract it from underground through expensive methods. 

Environmentally, gas firing is the next best solution when the circumstances are such that it cannot be extracted for use. 

At that time, expectations were that the gas would burn within days, but it is still burning, more than four decades after it was set on fire.