Norilsk is home to the world biggest mining and metallurgy complex, and is shut off from the world in more ways than one. 

Mysterious 'gigantic' hole in remote region spotted by helicopters over gas-rich Yamal peninsula.

Reindeer herders find more craters in the far north in a deepening puzzle for scientists. 

Most fires will not be extinguished, with major cities polluted by fumes.

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

The famously clear waters of Baikal - the world's deepest and oldest lake - are under threat from tourists, says leading scientist Maxim Timofeyev.

With smoke having blown as far as the US and Canada, experts now say 'the trend is positive' in controlling fires raging from the Urals to the Pacific.

Greenpeace claim authorities underestimate the scale of destruction, amid warnings of lack of resources to fight fires. 

Greenpeace concern as firefighters say they cannot extinguish 3 year blaze with smoke visible from space.