Intense search reveals no sign of Mil Mi-8 lost early Saturday with 12 people on board.
Russia could get a major boost from an influx of Chinese visitors.
Thermometers go above zero in places where the winter should be 20 or 30 degrees colder.
Same phenomenon of discharge of gas hydrates 'led to crater formation in Russia and disappearance of ships in Atlantic'.
Surgeon who suffered health issues turns to daredevil ski action on 'impossible' mountain slopes to relax.
Haunting beauty of massive hole as scientists examine frozen lake formed after giant blowout.
Emergency chiefs say that increased activity means tour companies and residents must avoid going too close to eruptions.
Exceptionally heavy snow falls lead to hunger and death for hardy animals.