Enrico Fermi — Chicago Pile-1

Under the stands of Stagg Field, on December 2, 1942, Enrico Fermi’s team achieved the world’s first self-sustaining nuclear chain reaction — built from 770,000 pounds of graphite and a wartime urgency that couldn’t wait for a proper lab.

Chicago Pile-1 quietly opened the atomic age, one squash court at a time.