Why did the United states start the Manhattan project?

The United States initiated the Manhattan Project during World War II in response to concerns that Nazi Germany was developing nuclear weapons. The project aimed to harness nuclear fission for military purposes and to ensure that the U.S. would not fall behind in atomic research. It ultimately resulted in the development of the first atomic bombs, which were used in 1945 to bring an end to the war in the Pacific. The project also marked a significant advancement in scientific research and technology.