July 16, 1945
First atomic bomb detonated
On July 16, 1945, the world's first atomic bomb is secretly detonated in the desert near Los Alamos, New Mexico. Under extreme secrecy, the British and Americans began development of the bomb in 1940. In 1942, the atomic program was placed under U.S. Army control and code-named the "Manhattan Project," and in 1943 a laboratory directed by U.S. physicist J. Robert Oppenheimer was opened in the New Mexico desert. By the time of the successful "Trinity" test in July 1945, more than $2 billion had been spent on the bomb's research and development. News of the deadly new weapon was not made public until three weeks later, when two others like it devastated the Japanese cities of Hiroshima and Nagasaki.