How do you save Paris from German World War I bombers? By building a life-sized decoy city, of course.
According to The Telegraph, the faux City of Light was created near the end of the war, in 1918, to draw German pilots away from the real Paris in the era before radar./
To deceive the German airmen, military planners went to great lengths recreating Paris’ famous quartiers and buildings. Along with a fake Arc de Triomphe, the French built a replica wooden Opera house, Gare Du Nord and Champs-Elysées. For verisimilitude, they added careful touches like translucent paint to mimic dirty glass roofs of factories. Alongside Hausmann’s boulevards, they constructed lifelike industrial suburbs.