On August 6, 1945, the first atomic bomb was dropped over the city of Hiroshima, Japan. The explosion instantly killed 80,000 people and destroyed 90% of the city. Tens of thousands of people then died of radiation exposure. On August 9th, another atomic bomb was dropped on Nagasaki, killing around 40,000 people. Japan’s Emperor Hirohito declared Japan’s surrender in World War II on August 15th.