The Italian-born physicist Enrico Fermi (1901–1954) was one of the chief architects of the nuclear age. In 1934 Fermi announced that he had discovered elements beyond uranium; but what he had really done, and which was later proved, was split the atom. In 1938, just before World War II (1939–45), this process was named nuclear fission. And one year later, German-born physicist Albert Einstein (1879–1955) would write a letter to President Franklin D. Roosevelt (1882–1945), urging the American government to study this process, which releases energy. Also in 1938 Fermi was awarded the Nobel prize in physics and he escaped Italy, where the fascist regime of Benito Mussolini (1883–1945) had taken hold. Fermi became a professor of physics at Columbia University in 1939, where he taught for three years. In 1942 he got involved in the Manhattan Project, which was developing the atomic bomb. In that capacity, he directed the first controlled nuclear chain reaction.

After World War II, Fermi, who had become an American citizen in 1944, taught at the University of Chicago and continued his research on the basic properties of nuclear particles. In 1953 he had an element named after him, fermium, an artificially created radioactive element. The U.S. Atomic Energy Commission (AEC) honors accomplishments in physics with the Enrico Fermi Award.