In 1939, a letter was delivered to Franklin D. Roosevelt informing him that the Germans had started work on a nuclear weapons program. The letter, written by Leó Szilárd, was signed by Albert Einstein. Roosevelt took the warning seriously and commissioned an Advisory Committee on Uranium to look into the element’s potential in warfare.

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In 1941, Pearl Harbour was attacked, and the US announced their intention to enter the war in an alliance with Britain, France and Russia. The Advisory Committee had a new role; it was now a military initiative.

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The Manhattan Project was born.

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US Army Colonel Groves was appointed to lead the project in 1942, and he went about collecting scientists to advise on the project. They were sent to work in remote locations across America and Canada. One of these scientists was J. Robert Oppenheimer, who was already working on nuclear fission when he was appointed director general of the Los Alamos Laboratory in 1943.

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The Manhattan Project was a great collaborative project involving scientists and engineers from across the world. Initially the military wanted to keep each division at Los Alamos under a strict code of silence, however Oppenheimer argued it would be best for the scientists to work together to ensure the quickest result. The scientists all lived and worked together, in what became known as the “secret city”. 

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The project successfully detonated the first atomic bomb on the 16th July 1945, in New Mexico. The explosion was known as the Trinity Test.

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Neither Otto Hahn nor Lise Meitner were there when the bomb was exploded. Weeks later, the first nuclear weapon was dropped in an act of aggression during war time.