The origin of it all...

The Tunguska Event, or Tunguska explosion, was a powerful explosion that occurred not far from the Podkamennaya (Lower Stony) Tunguska River in what is now Krasnoyarsk Krai in Russia, on June 30, 1908.

Although the cause of the explosion is the subject of debate, it is commonly believed to have been caused by the air burst of a large meteoroid or comet fragment at an altitude of 5–10 kilometres above the Earth's surface. Different studies have yielded varying estimates of the object's size, with general agreement that it was a few tens of metres across...