- American plan to develop nuclear weapons
- Run by Robert Oppenheimer
- Developed three bombs in 1945, "Trinity", "Little Boy" and "Fat Man"
- "Little Boy" a uranium bomb was detonated over Hiroshima
- "Fat Man" a plutonium bomb was dropped on Nagasaki
"The atomic bomb made the prospect of future war unendurable. It has led us up those last few steps to the mountain pass; and beyond there is a different country."
Major project throughout USA. Produced devastating bombs to end war.