This section provides an overview of the history of the Manhattan Project, the key organizations involved, the science behind the bomb, and more.
Doomsday Clock

Bulletin of the Atomic Scientists

The Bulletin of the Atomic Scientists is a journal founded in 1945 that analyzes nuclear policy challenges.
Castle Bravo. Image courtesy of Los Alamos National Laboratory.

Castle Bravo

On March 1, 1954, the United States carried out its largest nuclear detonation, “Castle Bravo,” at Bikini Atoll in the Marshall Islands. The Bravo explosion was more than two and a half times greater than expected and caused far higher levels of fallout and damage than scientists had predicted.
Graphite blocks

Chicago Pile-1

On December 2, 1942, Chicago Pile-1 went critical, creating the world’s first controlled, self-sustaining nuclear chain reaction.
US Government's No Trespassing Sign on Hanford Land

Civilian Displacement: Hanford, WA

Before the Manhattan Project, about two thousand people lived in White Bluffs, Hanford, and Richland, WA or nearby. For centuries, four different Native American tribes enjoyed the land along Columbia River.
Fuller Lodge on the Los Alamos Site, 1942

Civilian Displacement: Los Alamos, NM

To build the Los Alamos Laboratory, the Army took over the land of two dozen homesteaders, the Los Alamos Ranch School, and the Anchor Ranch.
Early Road Conditions in Oak Ridge (1942)

Civilian Displacement: Oak Ridge, TN

During the Manhattan Project, about 3,000 families and farmers from rural Eastern Tennessee were displaced for new research and development sites.
Joe-1 nuclear test

Cold War

The Cold War began shortly after WWII and plunged the world into a series of conflicts that would last more than forty years.

Combined Development Trust

The Combined Development Trust (CDT) was an effort spearheaded by General Leslie Groves to control the world market of uranium ore.
J. Robert Oppenheimer, John Von Neumann, and the MANIAC computer. Courtesy of the Shelby White and Leon Levy Archives Center, Institute for Advanced Study (IAS). © Alan Richards.

Computing and the Manhattan Project

The development of early computing benefited enormously from the Manhattan Project’s innovation.