This section provides an overview of the history of the Manhattan Project, the key organizations involved, the science behind the bomb, and more.
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.
Albert Einstein and Leo Szilard working on the famous letter

The Einstein-Szilard Letter - 1939

In 1939, Albert Einstein sent FDR a letter urging the US conduct research into an atomic bomb.
Fat man.

The Franck Report

Soon after the Interim Committee concluded that the atomic bomb should be used as soon as possible against Japan, a group of scientists led by physicist James Franck founded a committee to study the question of the bomb's use.

The Human Computers of Los Alamos

Before computers became the modern electric desktops or laptops of today, “computers” actually referred to the people who did computing or calculations of equations.
The bombing of Hiroshima

The Interim Committee

As the Manhattan Project neared its first atomic test, there was a growing sentiment among project leaders that an advisory committee to make recommendations on nuclear energy should be created.
The Manhattan Project insignia. Image courtesy of Alex Wellerstein.

The Manhattan Project

What was the Manhattan Project?

The Radium Girls

The tragic story of the "radium girls" had an important impact on the Manhattan Project.
The S-1 Committee in 1942: Harold Urey, Ernest Lawrence, James Conant, Lyman Briggs, Edgar Murphree and Arthur Compton

The S-1 Committee

As early as 1939, the U.S. government began to organize and fund nuclear research.
J. Robert Oppenheimer and General Leslie Groves after the Trinity Test

The Unlikely Pair

General Leslie Groves and J. Robert Oppenheimer were a study in contrasts, yet both were key to the Manhattan Project's success.