George Carey uncovers the mystery behind the massive explosion that shook Tunguska, Siberia in 1908 which has been variously attributed to a meteorite and a crashed UFO.
Here's some blurb I found [amongst others] on the Channel 4 feedback page which I thought was an interesting summary of the documentary's approach.
Siberia. Wild Russian Nature. Nat Geo Wild
Take a trek into Wild Russia to experience a land of fire and ice, polar bears and tigers.
Sprawling over 11 time zones and two continents from Europe to the Pacific, and beyond the magnificent cities of Moscow and St.