A cone of shattered limestone forty metres high in the remote taiga of Irkutsk Oblast, found by the geologist Vadim Kolpakov in 1949. The Evenks called it the Fire Eagle's Nest and kept away. Every explanation has been tried: meteorite, volcanic gas, an underground nuclear blast, a uranium deposit. None is confirmed, and the leader of the 2005 expedition died of a heart attack on the way to it, which did the reputation no harm.