The incredible meteor strike in Russia's Ural Mountains might make you wonder, has anything like this ever happened before?  We know that in prehistory we have evidence of large objects striking the earth.  Since 1900, the largest and best known meteor strike is the 1908 Tanguska Event.

Tanguska Event

The Tanguska Event, named for the isolated region in Siberia where the strike occurred, flattened over 700 square miles of forest.  Scientists have never proved definitively that Tanguska was caused by a meteor, but it's the most likely answer.

The Great Daylight Fireball

This event occurred over the Western United States and Canada in 1972. The asteroid did not strike the ground but got as close at 35 miles above the surface.  The event is known as a earth-grazing strike and is still considered an impact event.  The fireball was first spotted over Utah and exited the atmosphere above Alberta.