An explosion above the Podkamennaya Tunguska (Stony Tunguska) River region of central Siberia at about 7.30 a.m. local time on 1908 June 30, caused by a large stony meteorite or cometary fragment. A fireball as bright as the Sun detonated in mid-air, producing dust which caused abnormally bright nights across Europe for days afterwards. Expeditions to the site found a vast (2200 km²) area of devastation, with trees knocked over and scorched up to 40 km away, but no craters were found. The incoming body is thought to have been 50–100 m in diameter, and to have exploded 8–9 km above the ground with the energy of 15–20 megatonnes of TNT.