In the early 1900s, an East Tennessee logger named John Hendrix slept on the forest floor for 40 days and emerged to tell his neighbors that Bear Creek Valley would one day fill with great factories that would help win the greatest war ever fought. Nearly forty years later, the US Army Corps of Engineers arrived, bought roughly 60,000 acres at about $46 an acre, nailed eviction notices to doors, and built Oak Ridge, the secret city of the Manhattan Project.

This episode explores what happens when a government builds a civilization from scratch overnight for a single purpose. We look at why General Leslie Groves chose the ridged Clinch River Valley as a set of natural blast barriers, how a population of 3,000 became 75,000 in three years behind guard towers and seven gates, the prefabricated cemesto houses and uninsulated hutments, and the astonishing workaround of borrowing 14,700 tons of Treasury silver to wind electromagnets when copper ran out. We also confront the segregation hard-coded into the city, the Scarboro 85 who integrated its schools in 1955, the mercury contamination that made it a Superfund site, and its modern life as home to Oak Ridge National Laboratory.

• Governor Prentice Cooper tearing up the presidential proclamation and the bourbon-laced punch that smoothed things over
• Compartmentalization: how 75,000 residents worked without knowing what they were building
• The mile-long K-25 gaseous diffusion plant and the sandbox analogy for separating uranium-235
• The Spallation Neutron Source, supercomputers Titan and Summit, and element 117 named Tennessine
• Why data centers may be the secret cities of today’s technological arms race