1908 June 30th: Tunguska, Siberia

At 7.00am on 30th June 1908 near the lower Tunguska River, Siberia, a large explosion occurred.
The explosion was so massive that it caused damage 400 miles away, and was heard even further.
Even the heat that came out from the explosion was felt hundreds of miles away.
For several nights all over northern Europe, the sky glowed enough to light the street of London.
At first it was assumed that a massive meteorite had collided with the earth.

Given the remoteness of the area it was not until 1927 that an expedition was mounted to investigate the crash area.
The expedition could not locate any bits of meteorite which puzzled them due the size that the meteorite would have
to have been to create such a large explosion. Another puzzle for the expedition was the way the tress were felled in
an outward motion and that in the centre an area of trees were still standing, although all their bark and branches have
been destroyed.

After the Second World War and the bombing of Hiroshima and Nagasaki, photos of the cities were compared with
aerial photos of the Tunguska blast, and they were stunning similar.
As a result of this various scientists speculated that a nuclear explosion had taken place over the area, hence explaining
the tree formation, and because no nation possessed nuclear device the logical conclusion was that it was from an exploding
alien nuclear powered craft. Other theories started to be banded around ranging from pinpoint black holes, and antimatter particles.
Many of the witnesses to the original crash spoke of seeing and oval-shaped mass moving across the sky, as well as seeing the
object change course, and of having a very low speed.

Most people today believe that what hit Tunguska was simply a meteorite, but the alien craft theory still has a lot of credibility.
As with most of these cases that occurred long ago, we shall probably never know for sure.