Yamal Crater, Yamal Peninsula, Siberia, Russia

The 60-meter (66-yard) crater is believed by a senior researcher from the Scientific Research Center of the Arctic, Andrei Plekhanov, in remarks to the Associated Press, to be likely the result of a "buildup of excessive pressure" underground because of warming regional temperatures in that portion of Siberia. Tests conducted by Plekhanov's team showed unusually high concentrations of methane near the bottom of the sinkhole.
The scientists took various measurements and plan to provide more information soon on what may have caused the crater, which made headlines around the world when it was discovered. Many have speculated on its causes, often linking it to melting methane hydrate—an ice-like material frozen in the Arctic ground. A spokesperson for the Yamal branch of the Emergencies Ministry said, "We can definitely say that it’s not a meteorite."