Mystery of Siberia's giant exploding craters may finally be solved 

 Giant exploding craters only known to exist on Russia's permafrost-covered Yamal and Gydan peninsulas may result from a specific set of conditions not found elsewhere in the Arctic. 

https://cdn.mos.cms.futurecdn.net/Td93t9ocBpVCuafEszr3iX.jpg

https://www.space.com/mystery-of-siberias-giant-exploding-craters-may-finally-be-solved