The bombing of city of Hiroshima in Japan happened on August 6, 1945. The name of the bomb that was dropped on Hiroshima was "Little Boy". Little Boy was named after Franklin Delanor Roosevelt. `Three days later, the US bombed the city of Nagasaki. The bomb that was dropped on Nagasaki was called "Fat Man" and was named after Winston Churchill, the prime minister of the United Kingdom. A good amount of people make the common mistake of believing that the US dropped the bombs on the Japanese because of revenge for Pearl Harbor. The reason for the US bombing these two cities is that we wanted to force the Japanese surrender as quickly as possible to minimize American casualties. The firestorm in Hiroshima caused by the bombing ultimately destroyed 13 square kilometers of the entire city. Almost as much as 63 % of the building damaged or destroyed in the city. 92 % of the city's structures totaled by blast and fire. The estimated total death toll in the city of Hiroshima was expected to be around 100,000 and 180,000 people out of a population of 350,000 people. Approximately 22.7 % of Nagasaki's buildings were consumed by flames. Estimates of casualties from Nagasaki have generally ranged between 50,000 and 100,000 people.