Final answer:
The Manhattan Project was a top-secret effort during World War II, led by the United States with the goal of developing atomic bombs, which led to the bombings of Hiroshima and Nagasaki and significantly influenced global politics by initiating the atomic age.
Step-by-step explanation:
The Manhattan Project was a top-secret research initiative that began during World War II with the objective of constructing an atomic bomb. It started with the United States partnering with Great Britain, but eventually became a predominantly American effort. The project was associated with major figures like J. Robert Oppenheimer, who led the initiative, and scientists like Enrico Fermi and Glenn Seaborg, who made significant contributions.
The Manhattan Project began in earnest on December 6, 1941, with significant work kicking off following the attack on Pearl Harbor. The first self-sustained nuclear reactor achievement was in December 1942 at the University of Chicago, and by July 1945, the scientists succeeded in detonating the first atomic bomb at a test site in Los Alamos, New Mexico. The project culminated with the dropping of atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August 1945, leading to the end of World War II.
The impact of the Manhattan Project on world history is profound, as it not only hastened the end of World War II but also ushered in the atomic age, significantly influencing global politics, military strategy, and leading to the arms race during the Cold War.