Vital for making its waters so 'pure', one theory is that rising underwater methane leaks are killing off the sponge, but is there a silver lining?

Three man team probing the discovery is now 'missing in tundra', say Emergency Ministry officials.

Scientists say there is growing evidence that rising temperatures were catalyst for massive unexplained holes in ground.

Startling new details emerge of the most mysterious of Siberia's newly created giant permafrost holes.

Satellites show giant hole ringed by 20 'baby craters'.

Expert says deadly gas released from melting permafrost region will lead to 'awful' consequences for global warming.

Experts to visit remote craters to solve the puzzle on their creation.

Haunting beauty of massive hole as scientists examine frozen lake formed after giant blowout.

Men reunited with their families after successful operation to free them after fears  of gas leaks and more rock falls.