On the morning of June 30, 1908, the ground trembled in Central Siberia, and a series of flying fireballs, causing a “frightful sound” of explosions, were observed in the sky above the Stony Tunguska River. Strange glowing clouds, colorful sunsets, and a weak luminescence in the night were reported as far as Europe.
Likely many thousand people in a radius of 1.500 kilometers (or 900 miles) observed the Tunguska Event. However, due to the remoteness of the affected area, eyewitness testimonies were collected only more than half of a century after the event, and most were second-hand oral accounts. In 2008, unpublished material collected by Russian ethnographer Sev’yan Vainshtein resurfaced, including some first-hand accounts of the event.
Despite its notoriety in pop-culture, hard scientific data covering the Tunguska Event is sparse. Since 1928 more than forty expeditions have explored