What did scientist learn in the 1930s that ed to the Manhattan Project?

In the 1930s, scientists discovered nuclear fission, the process by which atomic nuclei split and release immense energy. This breakthrough, highlighted by experiments conducted by Otto Hahn and Fritz Strassmann, and later explained by Lise Meitner and Otto Frisch, demonstrated the potential for harnessing nuclear reactions for both energy and weaponry. Concerns about Nazi Germany developing atomic weapons spurred the U.S. government to initiate the Manhattan Project, aimed at developing an atomic bomb. This project ultimately led to the successful creation of nuclear weapons during World War II.