In 1939, Albert Einstein wrote a letter. Addressed to President Roosevelt, Einstein's letter described vast amounts of power derived from a nuclear chain reaction.

In 1942, a secret city in Tennessee was built as a production site for the Manhattan Project - the operation that created the atomic bomb.

Oak Ridge, Tennessee

Flat-top housing was a common style for Manhattan Project workers

Einstein and Szilard

Albert Einstein's 1939 letter to F.D. Roosevelt, President

Excerpt: may become possible to set up a nuclear chain reaction in a large mass of uranium, by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears almost certain that this could be achieved in the immediate future. This new phenomenon would also lead to the construction of bombs, and it is conceivable - though much less certain - that extremely powerful bombs of a new type may thus be constructed. A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port together with some of the surrounding territory..."

Little Boy was the codename for the bomb dropped on Hiroshima in August 1945. The Little Boy bomb contained enriched uranium produced in Oak Ridge.

Much of the Oak Ridge workforce discovered the results of their labors at the same time the world learned the news.

Nuclear fission occurs when an atomic nucleus is struck and splits into lighter atoms. The split releases energy in the form of gamma rays, heat, and neutrons.

The Mark 28 bomb is the oldest thermonuclear bomb in the US arsenal.

The newest bomb in the US weapons arsenal is the B 83 thermonuclear fusion bomb.

Scientists at Oak Ridge National Laboratory continue progress in neutron science, advanced materials, supercomputing and nuclear energy.

A supercomputer model demonstrates distributed computing using Raspberry Pi miniature computers at the American Museum of Science and Energy (

A tree slowly consumes a sign

The international friendship bell signifies the theme "Born of war, living for peace, growing through science" and incorporates the Oak Ridge-Japan historical link. The bell is the first U.S.-Japan monument at any Manhattan Project site.



Copyright © Oproot Research. All rights reserved. Permission is granted for limited, non-commercial use of these images. If used, please credit and notify Oproot Research. If circumstances permit, please include the URL: Oproot Research would appreciate a copy of publication. High-resolution images are also available. Please email requests, comments to