Stereoscopic photography (3D photography) is when two slightly offset photos are combined into one three-dimensional picture. It was a simple Victorian invention which brought the enemy landscape into 3D during the Second World War.
In 1830, a man called Sir Charles Wheatstone created an original binocular-type apparatus that later gave impetus to the appearance of the new photography genre.
Historical Notes: Some of the First World War was photographed in 3D. A Toronto photography studio stumbled across a stereoscopic camera, and its photographic slides, that captured scenes of the First World War in 3D. The photographs were taken in the trenches, streets, and battlefields of the First World War.
Use: By flying over German territory in planes outfitted with several cameras, pilots built a set of images that overlapped one another and could be viewed stereoscopically—that is, in 3-D. These three-dimensional images enabled the Allies to see such objects as camouflaged ships and V-1 rockets that would have not been easily spotted in ordinary images.