The Manhattan Project was the American-led research and development program, with support from the United Kingdom and Canada, that produced the first nuclear weapons during the Second World War. It followed a 1939 letter from Albert Einstein and Leo Szilard to President Roosevelt warning that Germany might build an atomic bomb. It grew into a vast effort under General Leslie Groves, with the physicist J. Robert Oppenheimer directing the weapons laboratory at Los Alamos, and sites at Oak Ridge and Hanford produced fissile material. The first test, Trinity, took place in New Mexico in July 1945, and bombs were dropped on Hiroshima and Nagasaki in August. The project opened the nuclear age and raised ethical debates that continue.
Before and after
- November 1938Kristallnacht
- 10 November 1938Death of Mustafa Kemal Atatürk
- 29 December 1938Birth of Jon Voight
- 1939Porajmos
- from 1939 to 1946Manhattan Project
- from 1939 to 1941Aktion T4
- 1939Founding of Marvel Comics
- 1939Publication of Thai National Anthem
- from 1939 to 1945Western Front
More in Science & technology
- 15 September 1917Launch of Forbes
- 1923Brønsted–Lowry acid–base theory
- 1927Hubble–Lemaître law
- 1936Alan Turing defines the universal machine
- from c. 1940s to 1960sGreen Revolution
- 1944Avery, MacLeod and McCarty show that DNA carries genes
The era
This moment belongs to the Modern era (1914 CE to 1945 CE), world wars and a changing world. You can also browse everything in the 20th century.