An enormous mysterious crater has left scientists scratching their heads after its discovery in northern Siberia.
Footage of the anomaly was filmed on Friday 11 July from a passing helicopter by engineer Konstantin Nikolaev as he and several others flew over the Russian peninsula called Yamal, which translates as "the end of the world".
The hole is roughly 30 kilometres from Yamal's biggest gas field Bovanenkovo. While the exact size of the crater is yet to be measured, the pilots believe it is wide enough to hold several Mi-8 helicopters inside.
You can watch the video below...
Is it the sign of a meteor strike? A sinkhole? Signs of a UFO landing on Earth? Numerous theories have circulated the web based on the apparent scorched earth around the hole and the soil thrown by whatever caused it.
Russian scientist Anna Kurchatova, from the Sub-Arctic Scientific Research Centre, has one theory, believing the simplest explanation is to blame: global warming.
Kurchatova's theory - reports The Siberian Times - stems from the local area's frozen soil, which over hundreds of years has trapped a mixture of gas, water and salt which when heated by the greenhouse effect could have built up enough pressure to result in an explosion likened to the pop of a champagne cork.
The Serbian Times also reports that an expedition to discover more about the hole is due with experts from Russia's Centre for the Study of the Arctic and the Cryosphere Institute of the Academy of Sciences on hand to help unearth the truth.
Soil, air and water samples are to be taken from the scene and a specialist from Russia's Emergencies Ministry will also accompany the team. A spokesman for the Ministry said: "We can definitely say that it is not a meteorite. No details yet."