On August 6, 1945, Enola Gay dropped the atomic bomb "Little Boy" on the city of Hiroshima, Japan. The explosion was estimated at 15 kilotons (or 15,000 tons of TNT). 70,000 people died within minutes or days; 100,000 died soon after (usually from radiation sickness). 200,000 died from long term effects (such as cancer).
On August 9, 1945, Bock's Car dropped "Fat Man" on the city of Nagasaki. 40,000 people died initially with 60,000 injured. 70,000 died by January and 140,000 within five years.