World War II began in 1939 in Europe. When Japanese bombed Pearl Harbor in 1941, America had an excuse to enter World War II. New weapons
were being created to advance the war. When the Germans discovered how
to split an atom, the key to creating atomic warfare, the United
States grew suspicious. As a result, President Roosevelt formed the
secret Manhattan Project to create atomic bombs and hopefully end the
massive war. In 1945 American troops became the first to ever use
atomic bombs as a weapon source in the history of any war. Success
came as the Japanese surrendered just days after the bombs were
dropped.