Manhattan Project

Manhattan Project, wartime project begun in 1942 to develop nuclear weapons. A team headed by Enrico Fermi initiated the 1st self-sustaining nuclear chain reaction. In order to obtain the necessary amounts of the required isotopes, uranium-235 and plutonium-239, centers were established in Tennessee and Washington. Actual design and construction of the atomic bombs was carried out at Los Alamos, N.M., by a group headed by J. Robert Oppenheimer. On July 16, 1945, the first atomic bomb was detonated near Alamogordo, N.M. The following month a uranium bomb was dropped on Hiroshima (Aug. 6) and a plutonium bomb on Nagasaki (Aug. 9).