The invention of atomic weapons was the result of the political and scientific progress made in the 1930s. The development of fascist regimes, scientific progress and the need to counter the alleged intentions of Nazi Germany to create an atomic bomb, led to the collective decision of the US, the UK, and Canada to develop their own powerful weapons based on nuclear fission. The product of their collaboration – called the Manhattan Project – culminated in the Trinity test detonation, the first ever nuclear explosion. The Trinity test took place on the 16th of July in 1945 in the Alamogordo Desert.
Three weeks later, in the morning of August 6th, the US dropped a uranium device called Little Boy on the Japanese city of Hiroshima, thus marking the first military use of a nuclear weapon. The second nuclear device was dropped on August 9th 1945, destroying large parts of the city of Nagasaki. This time, the US used a plutonium implosion-type device known under its code name Fat Man. The Hiroshima and Nagasaki bombings claimed approximately 200,000 lives.