Scientists have finally descended into one of the three enormous holes that mysteriously opened up in Siberia several months ago. The holes, on Russia’s Yamal Pensinsula, captured attention after one was first spotted by an aircraft pilot in July, who took this pic: The world went mad. Suspected causes ranged from meteorites to underground explosions to extra-terrestrial. Now a team from the Russian Centre of Arctic Exploration has climbed down to the bottom of the largest hole, about 16m, to stand on a frozen lake which itself is about another 10.5m deep. The team had to brave winter temperatures of...