3D Photos
The technique to look at these photos is to cross your eyes and bring the 2 images together then refocus your eyes. Probably a lot easier than trying to view stereograms which were popular a few years ago where there was no visible image to see. If you would like to experiment with 3D photography there are 2 very reasonably priced cameras at The Widescreen Centre and a beamsplitter attachment for 35mm cameras but make sure you know what type of lense mount you have. Absolutely no special developing or printing is required with these and there is a viewer that comes with the cameras. For more technical info on these and more 3D links go to Loreo or try Stereoscopy.com .