Tunguska Event (~30 Jun 1908).

The Tunguska event of 30 June 1908 was an enormous air-burst over the Podkamennaya Tunguska region of Siberia that flattened an estimated 2,150 square kilometers of forest with no impact crater. Scientific consensus attributes it to the atmospheric explosion of a stony asteroid or comet fragment. It matters here because, especially after 1946, fringe writers proposed it was a crashed alien craft or a nuclear-powered spaceship; that extraterrestrial reading is fringe, while the bolide air-burst explanation is well supported.