On December 2, 1942, beneath the bleachers of a squash court at the University of Chicago, Enrico Fermi achieved the first controlled, self-sustaining nuclear chain reaction — a moment that proved atomic energy was real and made the atomic bomb inevitable. Fermi was the rare physicist equally brilliant as theorist and experimentalist, and the reactor he built changed the course of history.

This episode traces Fermi from his precocious youth in Rome through his Nobel Prize-winning work on neutron bombardment, his flight from Fascist Italy to protect his Jewish wife, and the Manhattan Project work that made him one of the most consequential scientists of the twentieth century.

• Fermi's early genius and the legendary "Via Panisperna boys" physics group in Rome
• The neutron experiments that won the Nobel Prize and accidentally  ...