The Tunguska Event

On June 30, 1908, a massive explosion over Siberia flattened approximately 800 square miles of forest. The blast, estimated at 10-15 megatons, was heard 600 miles away. No crater was found.

Residents observed a brilliant light, then an explosion that knocked people down 40 miles away. Trees were flattened in a butterfly pattern. The explosion was detected by seismographs across Eurasia.

The leading explanation is an air burst of a comet or asteroid approximately 200 feet across, exploding before impact. Alternative theories include a natural nuclear explosion or antimatter collision.

The Tunguska event remains the largest impact event in recorded history.