You may think of virtual reality as a modern form of entertainment, but its roots lie in the late 19th to early 20th centuries. These cards, called stereographs, consist of two nearly identical photographs or photomechanical prints, paired to produce the illusion of a single three-dimensional image, usually when viewed through a stereoscope.
Typically, the images are on card mounts, but they may take the form of daguerreotypes, glass negatives, or other processes. Stereographs were first made in the 1850s and were most popular between 1870 and 1920. Providing an affordable form of entertainment and educational captions, stereographs were extremely popular amongst the middle-class.
