World War II: the Atomic bombing of Hiroshima. An atomic bomb codenamed Little Boy is dropped by the American B-29 Enola Gay on the city of Hiroshima in Japan at 8:16 a.m., killing 80,000 outright with another 60,000 dead by the end of the year due to fallout sickness. Ultimately, about 200,000 die due to the atomic bomb.