where and when?:The Tunguska explosion occurred on the morning of June 30, 1908 at 7:17 A.M. local time (0h 17m 11s U.T.) in the area of the Stony Tunguska River with the coordinates of the epicenter being 60º55' N, 101º57' E (Kridec 1966). This location is in the central Siberian area of Russia, approximately 1000 km north of the town of Irkutsk and Lake Baikal (Figure 1).what happened?:a huge fireball crossed the night sky and then exploded! Who investigated it first?:Leonid Kulik is the first!What did the scientists find out later Can we explain the mystery now?:At the moment it is still a mystery!=)