At 3:25 P.M. on December 2, 1942, the Atomic Age began inside an enormous tent on a squash court under the stands of the University of Chicago’s Stagg Field. There, scientists headed by Enrico Fermi engineered the first controlled nuclear fission chain reaction. The result, sustainable nuclear energy, led to creation of the atomic bomb and nuclear power plants—two of the twentieth century’s most powerful and controversial achievements.