This section provides an overview of the history of the Manhattan Project, the key organizations involved, the science behind the bomb, and more.
A ruined synagogue in Eisenach after Kristallnacht in 1938

Scientific Exodus

A startling proportion of the most famous names on the Manhattan Project belonged to scientists who came to England or America to flee from the Axis.
Smyth Report

Secrecy Unveiled - 1945

Henry DeWolf Smyth prepared the official U.S. government history about the development of the atomic bombs.
The Los Alamos main gate

Security and Secrecy

A key component of keeping the Manhattan Project secret was making sure Project sites were secret and secure.
Joe-1 (replica)

Soviet Atomic Program - 1946

Soviet physicists paid close attention to the news of the discovery of fission in Germany in 1938, and began research shortly thereafter.
A checkpoint in Zheleznogorsk, a closed city in Krasnoyarsk Krai, Russia

Soviet Closed Cities

The sprawling nuclear complex across the Soviet Union included entire cities that were kept closely guarded secrets.

Soviet Hydrogen Bomb Program

The successful test of RDS-1 in August of 1949 inspired the Soviet government to institute a major, high-priority program to develop the hydrogen bomb.
World War II poster

Special Engineer Detachment

The Army tapped the vast pool of GIs possessing scientific and technical backgrounds, assigning them to the Special Engineer Detachment.
Manhattan Project Survey Team in Hiroshima. Photo courtesy of the Patricia Cox Owen Collection, AHF.

Surveys of Hiroshima and Nagasaki

Manhattan Project members participated in early missions to survey the two atomic bombing sites—Hiroshima and Nagasaki—after the Japanese surrender in August 1945.
The Hiroshima Atomic Dome, the only building left standing near the epicenter of the bombing.

Survivors of Hiroshima and Nagasaki

By the end of 1945, the atomic bombings of Japan had killed an estimated 140,000 people at Hiroshima and 74,000 at Nagasaki. Often lost in those numbers are the experiences of the survivors, known as the hibakusha.