A key figure in the development of nuclear fission, Enrico Fermi was an Italian physicist who worked in the United States on the Manhattan Project, the top-secret plan to develop the world's first atomic bomb. Fermi became a professor of physics at the University of Rome in 1926. After the discovery of the neutron in 1932 by James Chadwick, Fermi turned his attention to the idea that bombarding elements with neutral particles could cause transmutations and create new elements not found in nature. His work earned him the Nobel Prize in 1938 and put him on the path of creating uranium fission. Immediately after accepting the prize in Stockholm, Fermi and his wife moved to the U.S. to escape the fascist government of Italy's Benito Mussolini
. Fermi worked in the physics department of Columbia University (1939-42) before being assigned as one of the directors of the Manhattan Project with J. Robert Oppenheimer
. On 2 December 1942, in a squash court at the University of Chicago, the world's first nuclear reactor was demonstrated under Fermi's direction, paving the way for the completion of the atomic bombs dropped on Japan in August 1945 on the orders of President Harry S. Truman
. In 1945 he accepted a position with the Institute for Nuclear Studies at the University of Chicago, where he worked on theoretical and practical physics until his death from stomach cancer at the age of 53.