![People stand on the edge of the giant Yamal crater, which has almost filled with water since it erupted.](https://cdn.mos.cms.futurecdn.net/CTQ96wzZXRe4yk5AEFfkvm-320-80.jpg)
Methane 'kitchens' in Siberia's permafrost form mounds that can erupt, creating giant craters
A buildup of methane and other fluids in open and closed "systems" in the permafrost could explain why strange, icy mounds sometimes erupt to form giant crater, researchers say.