The Tunguska event was a large explosion of between 3 and 50 megatons TNT equivalent that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate, Russia, on the morning of 30 June 1908
Trees knocked down and burned by the blast. (image from over two decades after the event)
Tunguska marshes, near the site of the explosion. This photo was published in the magazine Around the World in 1931. The original photo was taken between 1927 and 1930 (presumptively no later than 14 September 1930).[citation needed]
Sample of burn damaged tree, museum of Moscow State University
Thin section of a fragment of "John's stone" from the epicentre of the Tunguska event. "John's stone" was suspected of being a Tunguska meteorite fragment, but is in fact a metamorphic, terrestrial rock.