1950s Soviet atom bomb test and effects. Footage of the detonation of an atomic bomb, and the resulting effects, during a Soviet nuclear test in the 1950s at the Semipalatinsk Test Site in what is now Kazakhstan. This footage shows the formation of the characteristic mushroom cloud, followed by trees being destroyed by the shockwave. A total of 456 nuclear tests were conducted at the Semipalatinsk site between 1949 and 1989.