On July 24, 1945, through an interpreter, President Harry S. Truman hints to Soviet Premier Joseph Stalin that the United States has successfully developed a new weapon. In his diary, Truman privately referred to the new weapon, the atomic bomb, as the most terrible bomb in the history of the world.
The United States had successfully tested the world’s first atomic weapon near Alamogordo, New Mexico, on July 16, 1945. Truman received the news while in Potsdam, Germany, conferring with British Prime Minister Winston Churchill and Soviet leader Joseph Stalin on post-World War II policy in Europe. On July 17, Truman told Churchill of the test’s success and the two agreed to put off telling Stalin about what Truman called the dynamite news until later—Truman first wanted to get Stalin to agree to enter the Pacific war on the Allies’ side with no strings on it.