A decade ago, a mysterious crater appeared in the Russian Arctic, forming a huge jagged hole hundreds of feet wide. Since then more than 20 have formed, leaving scientists baffled and intrigued

That's the puzzle scientists have been wrestling with since 2014, when the first 100-foot-wide crater burst through soil that had been frozen solid for hundreds of thousands of years. Since then, numerous craters have followed in the first one's wake,

In the remote Siberian tundra, the ground itself has begun to explode. Since 2014, more than 20 mysterious craters, each hundreds of feet wide, have torn open the Russian Arctic’s permafrost, leaving behind jagged holes filled with inky darkness.

Since 2014, mysterious craters have started appearing in the northwestern part of Siberia. New holes in the ground are causing a significant stir, and researchers are trying to understand the mechanism of their formation.