Hiroshima The United States during the 1930’s was interest in making a weapon that was so powerful that it would be feared by the world. Then in 1939 a German-American physicist by the name of Albert Einstein sent a letter to then President Franklin D. Roosevelt about the his new discovery and to warn about it’s potential. The U.S. government establish a top secret plan called the Manhattan Project to develop the atomic bomb. By July 16, 1945 the U.S. government had tested the bomb. The U.S. deeply determine to bring an end to the war with Japan decided to do what was to be one of the most deadly bombing in human history. Then on August 6, 1945 under the approval of