Tunguska

Referred to by Sulu, this is an area in Siberia that in 1908, a unknown phenomena had taken place. In this, a unknown object had exploded over this area with the force of a ten to twenty megaton H-bomb. It is theorized that a meteorite had hit the area, but some have speculated that a alien ship had exploded there in 1908. See the Wikipedia article:Tunguska