Scientists say there is growing evidence that rising temperatures were catalyst for massive unexplained holes in ground.
Independent film makers from around the world choose Siberia.
The only Russian victim was from Irkutsk, say reports.
Cases of mother bears successfully raising 'twins' in captivity are extremely rare.
Karina became the symbol of resilience and hope when - aged only 4 - she survived 12 days in taiga of Yakutia.
Satellites show giant hole ringed by 20 'baby craters'.
Russian foreign minister Sergei Lavrov and US secretary of state John Kerry will attend the May 14-15 Arctic Council in Kiruna, Sweden.
A future international tourist bonanza is being brewed on the historic Great Tea Road.
Major bid to check radioactive waste dump area in Arctic archipelago.