What was the Tunguska event?

The Tunguska event was a huge explosion that occurred in the sky near the Stony Tunguska River, in Yeniseysk Governorate (now Krasnoyarsk Krai), Russian Empire, on the morning of 30 June 1908. The explosion over the sparsely populated Eastern Siberian Taiga, flattened 2,000 km2 (770 sq mi) of forest. Due in part to the remoteness and the sparse population of the region, there were no known casualties among humans. The cause of the explosion is generally thought to have been a meteor. It is classified as an impact event, even though no impact crater has been found. The meteor is thought to have exploded in mid-air at an altitude of 5 to 10 kilometres (3 to 6 miles) rather than hitting the surface of the Earth.

Different studies have yielded varying estimates of the bolide's size, on the order of 60 to 190 metres (200 to 620 feet). These variations depend on speculations whether the object originated from a comet or an asteroid. It is the largest known impact event on Earth in recorded history.