Looking Back at the Dawn of the Atomic Age

In 1939, Albert Einstein wrote a letter to President Roosevelt warning about the risk of Nazi Germany acquiring nuclear weaponry. But it was only after the Japanese attack on Pearl Harbor that the War Department began a serious research project to build an atomic bomb.

Los Alamos Ranch School

A private boarding school for boys, the Los Alamos Ranch School, as well as the surrounding land, was bought in February 1943 by the U.S. government to house what would become the main research area for the Manhattan Project.

Checkpoint at Main Gate

A Town Rises in the Desert

J. Robert Oppenheimer

J. Robert Oppenheimer, a physicist at the University of California, Berkeley, was selected to be the scientific director of the Manhattan Project.

Gen. Leslie Groves

General Leslie Groves, military head of the Manhattan Project - so named because the first headquarters was located in New York City.

Tower Built for first Atomic Bomb Test

A 100-foot-tall tower was built for the test.

Plutonium Gun Bomb Casings for "Thin Man"

Scientists toyed with the idea for a plutonium gun-type bomb, also known as "Thin Man". The idea was later abandoned in favor of an alternative detonation using implosion.

The "Gadget" Prior to the Trinity test

Picture of "the gadget," as the test bomb was called, as the device was loaded into position. Norris Bradbury is the man on the left. He later led the Los Alamos facility from 1945 until 1970.

Schematic of a Gun-Type Nuclear Bomb

After consideration, the plans for the "Thin Man" nuclear bomb, a proposed plutonium gun-type nuclear bomb, were abandoned.

Color Image of the Trinity Blast

The only existing color photo of the Trinity explosion.

Another View of the Trinity Explosion

Trinity Bast Site after the Test

Aerial view of the aftermath of the Trinity test

Oppenheimer Examines the Post-Blast Site

J. Robert Oppenheimer (in light colored hat with left foot on tower rubble) pictured examining the aftermath of the Trinity blast with General Leslie Groves and others.