In the late 1950s, one of the most consequential artifacts of the twentieth century sat rusting on an overgrown stretch of tarmac in Maryland, with birds nesting in its engine cowlings and souvenir hunters unbolting pieces to take home. This episode traces the life cycle of the Boeing B-29 Superfortress Enola Gay, from the Silverplate specification that stripped its armor and gun turrets and added fuel-injected engines, reversible-pitch propellers, and pneumatic bomb bay doors, to Colonel Paul Tibbets personally selecting it on the assembly line in Bellevue, Nebraska, in May 1945 and naming it for his mother the day before the mission.

The episode follows the Hiroshima mission in detail: the uranium projectile welded to the floor of the captain's quarters aboard the USS Indianapolis, the bomb armed in flight to avoid vaporizing Tinian in a  ...