When was the first atomic bomb tested?

The first atomic bomb was detonated in the Trinity test on 16 July 1945 at the Jornada del Muerto desert in New Mexico, United States. It was part of the Manhattan Project, the secret Allied wartime program to develop nuclear weapons. The test used a plutonium implosion device and produced a blast far beyond anything previously seen. Just weeks later, atomic bombs were dropped on Hiroshima and Nagasaki in August 1945. The Trinity test marked the beginning of the nuclear age.