In order to confuse enemy aircraft during World War II, the residents of Hamburg disguised the Binnenalster, a lake in the main business district, as terrain and built a dummy viaduct parallel to the real viaduct, in effect “moving” an attractive target to a less vulnerable location.

Unfortunately the work was done in daylight and the change was too dramatic to be convincing. “Even so, the protection must have been of real value at least in Hamburg, where the addition of a dummy viaduct, displaced from, but parallel to, the real (Lombard’s) viaduct may have contributed to saving the latter very vital rail and transportation link.”

(U.S. Strategic Bombing Survey, Civilian Defense Division Final Report: Dates of Survey: 15 Jan.-15 Aug. 1945, 1947.)