US develops at atomic bombs (nov 25, 1942 – jul 16, 1945)

Description:

This was during the Manhattan Project. The US first tested it in the Trinity test, in New Mexico, on 16 Jul 1945. Atomic bombs would be used on Japan about a month later.

The USA kept it a secret from the USSR. However Stalin knew about it because of his spies.
Stalin was worried that the USA kept it a secret from them because they wanted to make sure they are the only country in the world with the atomic bomb and to keep USSR weak through these bombs.

- USSR then went ahead and develop their own atomic bombs by 1949
- This led to an arms race between both countries and the start of the Cold War

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