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
Anti-nuclear movement in the United States surveys showed rising public uneasiness about the nuclear arms race—especially atmospheric nuclear weapons tests that sent radioactive fallout around the globe. In 1962, Linus Pauling won the Nobel Peace Prize for his work to stop the atmospheric testing of nuclear weapons, and the "Ban the Bomb" movement spread throughout the United States. Between 1945 and 1992, the United States maintained a program of vigorous nuclear weapons testing. A total of 1,054 nuclear tests and two nuclear attacks were conducted, with over 900 of them at the Nevada Test Site, and ten on miscellaneous sites in the United States (Alaska, Colorado,