In 1945 two atomic weapons were used against Japan .
The atomic bombings of Japan took place in August of 1945. While there were numerous nuclear tests on U.S. soil, no atomic bomb was dropped on the U.S. Japan is the only country to have suffered such an attack.
It was December 8th 1941 when the US dropped the bombs on Japan.
The first atomic weapon used in combat was dropped on Hiroshima, Japan on 9 August 1945. The second was dropped three days later, this time on Nagasaki, Japan.
The Atomic bomb was dropped onto Japan in 1945 and WW2 ended on 1945, so it didn't take year(s) off WW2. It took 3 weeks and 2 days for WW2 to officially end after the 2nd atomic bomb was dropped onto Japan.
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The atomic bomb was invented in 1933 by Leo Szilard, but it took the Manhattan Project (1942 to 1947) to actually build the first ones.
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