Australian toy photographer Ray of ToyShoots recently purchased this old school stereoscope that was apparently manufactured in 1896. It's the device people used to view stereoscopic photos as one 3D image (the View-Master, which was released in 1936, is also a stereoscope).
Paris-based photo enthusiast Alexis was passing a thrift store near his home recently when he noticed some strange looking optical equipment. Upon entering the shop for a better view, he discovered that it was an old stereograph viewer with ground glass in the rear. The store owner informed him that the viewer came with a box of roughly 50 glass plates made in France in the 1930s. Alexis jumped on the deal and, upon returning home, was pleasantly surprised to find that the images were beautiful 3D photographs of what living in France was like nearly a century ago.
The New York Public Library has a massive collection of over 40,000 vintage stereographs (two photos taken from slightly different points of view). To properly share them with the world in 3D, the library has launched a new tool called the Stereogranimator. It lets you convert an old stereograph into either an animated 3D GIF (which uses "wiggle stereoscopy") or an anaglyph (the kind that requires special glasses).