Nuclear fission Mexico, which was the scientific hub for research on bomb development and design. Other sites, notably the Berkeley Radiation Laboratory and the Metallurgical Laboratory at the University of Chicago, played important contributing roles. Overall scientific direction of the project was managed by the physicist J. Robert Oppenheimer. In July 1945, the first atomic explosive device, dubbed "Trinity", was detonated in the New Mexico desert. It was fueled by plutonium created at Hanford. In August 1945, two more atomic devices – "Little Boy", a uranium-235 bomb, and "Fat Man", a plutonium bomb – were used against the Japanese cities of Hiroshima
B28 nuclear bomb several subsequent weapons. The B28 was the mainstay of SAC during the Cold War and have yet to be completely dismantled by the Defense Department (as of 2012). Nuclear researcher Chuck Hansen's research indicates that the Python primary was used in the US B28 nuclear bomb and the W28, W40, and W49 nuclear warheads. Four Mark 28 training variants (BDU-16/E) on their transporter (MHU-7/M) are on display in the Cold War Gallery at the National Museum of the United States Air Force in Dayton, Ohio. The Canadian War Museum, in Ottawa, holds a Mark 28RE training variant in its Cold