Final answer:
The Manhattan Project was a top-secret organization in World War II that developed the first atomic weapon.
Step-by-step explanation:
The Manhattan Project was an organization created to develop an atomic weapon. It was a top-secret project led by the United States during World War II. The goal of the project was to design and build the first atomic bomb. The project was successful, and the bombs developed under the Manhattan Project were later used in the bombings of Hiroshima and Nagasaki in Japan.
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