A project planned by the USA in 1940 for developing and manufacturing an atomic bomb. In 1939, physicist, Leo Szilard, proposed the development of an atomic bomb in a latter addressed to President Roosevelt that was signed by theoretical physicist, Albert Einstein. He hinted that it could eventually have military applications. In 1942, a group of scientists headed by physicist, Robert Oppenheimer, established a laboratory in Los Alamos, New Mexico. Development was carried out in absolute secrecy.
The atomic bomb was created and then dropped on Hiroshima, Japan on August 6, 1945, and again on Nagasaki, Japan on August 9.