Fort Knox is shorthand for an impenetrable gold vault, yet the vault is a small part of a 109,000-acre installation spread across Bullitt, Hardin, and Meade counties in Kentucky. This episode follows the land itself, beginning in 1861 when Union forces built Fort Duffield on high ground above the Salt and Ohio rivers. The Army returned in 1918 to train field artillery, named the camp for Henry Knox, and then, after postwar budget cuts, let it become the Camp Henry Knox National Forest from 1925 to 1928.

Mechanized cavalry arrived in 1931, and the shock of the German blitzkrieg turned the post into the proving ground for American armored doctrine, with 3,820 buildings by 1943. The Treasury added the Bullion Depository in 1936, guarded by the United States Mint Police rather than the Army. The episode continues through a 1947 public relations experiment in gentler boot camp, the filming of Stripes, the armor school’s 2011 move to Fort Benning, and the base’s new life as home to Army Human Resources Command.

• The first gold shipments, almost 13,000 metric tons, were escorted to the depository by the 1st U.S. Cavalry Regiment in combat cars.
• After Pearl Harbor, the Declaration of Independence, the Constitution, and the Gettysburg Address were stored in the vault until September 1944.
• The Universal Military Training Experimental Unit mandated chapel attendance and banned drill instructors from swearing to sell a peacetime draft to wary parents.
• The Patton Museum holds Foam 161, a fire truck charred and partly melted while responding to the September 11 attack on the Pentagon.
• With trainees replaced by a smaller permanent headquarters workforce, the local population fell from over 12,000 in 2000 to around 7,700 in 2020.