The Manhattan Project

The Manhattan Project was a top-secret research and development undertaking during <a href="/article/world-war-ii">World War II</a>, primarily led by the United States with support from the United Kingdom and Canada. Its ultimate goal was to develop the world's first <a href="/article/nuclear-weapons">nuclear weapons</a>, fundamentally altering warfare and international relations. This massive scientific and industrial effort successfully produced the atomic bombs used in August 1945.