The United States is the first and only to use nuclear weapons in the history of world. These attacks came in August, 1945, during final stages of World War II against the of Japan. Two cities targeted by the U.S. Hiroshima, and Nagasaki. The war in Europe was in May of that year, with Nazi Germany's , but the Japanese carried on. The U.S. and allies conducted a firebombing campaign against the Japanese. devastated the country, but they would not surrender. allies were looking at a costly campaign to the Japanese mainland. The Japanese were determined to to the last person to defend their country, necessary. This was a major factor in the to use the atomic bomb.

The U.S., along China and the United Kingdom, called for Japan's in July 1945 with a threat of devastation, Japan refused. On August 9, the first bomb dropped on the city of Hiroshima. Nicknamed "Little ," the bomb killed approximately 90,000 to 170,000 Japanese . The blast completely destroyed the city. Three days , a second bomb, nicknamed "Fat Man," destroyed the of Nagasaki. That bomb killed an estimated 60,000 - ,000 Japanese citizens. About half of the total were immediate. The remainder of the deaths came after, when the survivors of the initial blast sick from radiation poisoning, and injuries.

On August , after the two atomic bomb attacks, and a of war on Japan by the Soviet Union, decided to surrender. The reasoning behind the decision use nuclear weapons on Japan is debated to date. Many say that the bombs saved Japanese, American lives. The argument is that because of determination, many more lives would have been lost. any event, the two attacks are the only attacks in world history.