Officials insist there is no problem but this is not how locals see it in Cheremkhovo town.

Subsidence from old coal mine a possible cause of latest mystery hole.

Local reindeer herder witnessed the tundra explosion that led to birth of new hole in river.

A methane explosion at  Mine No. 7 in the Prokopyevsky district of Kemerovo region led to the deaths of four miners.

Same phenomenon of discharge of gas hydrates 'led to crater formation in Russia and disappearance of ships in Atlantic'.

Concern from scientists over potential danger to gas production facilities in region vital for energy supplies.

Blocks of soil and ice thrown hundreds of metres from epicentre of the funnel at the Yamal peninsula.

Giant holes created when pingos erupted after filling with gas.

Dissecting them like surgical abscesses to release the gas seen as one solution to avoid future eruptions.