What year did the Americans build the attomic bomb?

The Americans developed the atomic bomb during World War II as part of the Manhattan Project, which began in 1942. The first successful test of an atomic bomb, known as the Trinity Test, took place on July 16, 1945, in New Mexico. Subsequently, atomic bombs were dropped on the Japanese cities of Hiroshima and Nagasaki in August 1945, leading to the end of the war.