The Manhattan Project Legacy
How the secret wartime program that built the first atomic bombs shaped nuclear policy, scientific ethics, and the arms race for decades to come.
Building the Bomb
The Manhattan Project was the largest secret scientific endeavor in history. Launched in 1942 under the leadership of General Leslie Groves and physicist J. Robert Oppenheimer, the project employed over 125,000 people across dozens of sites, most notably Los Alamos in New Mexico, Oak Ridge in Tennessee, and Hanford in Washington state. The total cost was roughly $2 billion (equivalent to over $30 billion today). Most workers had no idea they were building a weapon.
The project succeeded in producing two types of atomic bombs. 'Little Boy,' a uranium gun-type weapon, was dropped on Hiroshima on August 6, 1945, killing approximately 80,000 people instantly and tens of thousands more from radiation and injuries. 'Fat Man,' a plutonium implosion device, devastated Nagasaki three days later. Japan surrendered on August 15. The use of atomic weapons remains the most morally debated decision in military history.
