Two giant holes were found in Yamal-Nenets Autonomous Okrug in 2014. They appeared as a result of gas emissions. A frozen lake has been found in one of the holes, at least proving that it isn't bottomless. One of them has a diameter of 60 meters and a depth of 200 meters, although it is still growing.
After the appearance of the mysterious holes, experts began to investigate their origin, offering theories as diverse as an underground explosion, a meteorite fall, and technogenesis.
