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Albert Einstein and Hungarian physicist Leo Szilard drafted a letter to Presiden
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August 2

Einstein Urges FDR: Build the Atomic Bomb

Albert Einstein and Hungarian physicist Leo Szilard drafted a letter to President Franklin Roosevelt on August 2, 1939, warning that Nazi Germany might develop an atomic bomb. Einstein signed it, lending his fame to Szilard's urgency. The letter described how uranium chain reactions could generate "vast amounts of power" and create "extremely powerful bombs of a new type." Roosevelt received the letter on October 11, 1939, and established the Advisory Committee on Uranium, which eventually grew into the Manhattan Project. Einstein himself never worked on the bomb and later called the letter "the one great mistake in my life." The $2 billion project he helped initiate produced the weapons dropped on Hiroshima and Nagasaki.

August 2, 1939

87 years ago

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