Manhattan Project
Overview
The Manhattan Project was a top-secret US government program that developed the world’s first atomic weapons. In 1938, scientists in Germany discovered nuclear fission—the splitting of an atom that releases enormous energy.
Fearing Nazi Germany might build an atomic bomb, President Franklin D. Roosevelt authorized advisory committees to study nuclear weapons—efforts that evolved into the Manhattan Project in 1942. The program was overseen by the US Army Corps of Engineers under the direction of General Leslie Groves, with physicist J. Robert Oppenheimer serving as scientific director.
Work took place across three primary sites—Oak Ridge, Tennessee; Hanford, Washington; and Los Alamos, New Mexico—where scientists produced the fissile material and designs for the first nuclear weapons. The project culminated in the Trinity test in July 1945, when a plutonium implosion bomb was detonated in the New Mexico desert.
The Manhattan Project cost an estimated $27B in today’s dollars and ushered the world into the atomic era, reshaping global warfare, diplomacy, and the balance of power.
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