The focus of the Manhattan Project during World War II was the development of atomic weapons. Launched in response to fears that Nazi Germany would create a nuclear bomb, the project brought together some of the world's most brilliant scientists, including J. Robert Oppenheimer and Enrico Fermi. Secret laboratories across the U.S. developed the first atomic bombs, leading to the bombings of Hiroshima and Nagasaki in 1945. The successful detonation of atomic bombs led to Japan's surrender and the end of World War II, but it also initiated a new era of nuclear weapons and raised ethical questions about their use and consequences.