During Gibraltar's Great Siege (1779-1783), Sergeant-Major Henry Ince proposed tunneling the Rock for cannons. Royal Engineers expanded these tunnels during WWII, creating 33 miles of passages, now a historical site with military displays.
Parisian public urinals (vespasiennes), initially for hygiene, became sites for secretive activity, resistance communication during WWII, and even unique subcultures. Only one remains today.
The Desert Training Center (DTC) in the Mojave Desert, established by Patton to train soldiers for North African combat during WWII, hosted nearly a million troops. Remnants of camps and training grounds remain.
