Details: This poster shows a mushroom cloud from an atomic bomb explosion. At the bottom it says Operation Crossroads - Baker Test - July 24 1946: 21 Kilotron Sub-Surface Burst - Marshall Islands - Bikini Atoll Lagoon.
A nuclear weapon is a weapon which derives its destructive force from nuclear reactions of fission or fusion. In the history of warfare, nuclear weapons have been used only twice, both during the closing days of World War II on the Japanese cities of Hiroshima and Nagasaki. Since these bombings, nuclear weapons have been detonated on over two thousand occasions for testing and demonstration purposes.