Stereo Photography simply refers to two pictures of the a subject taken at the same time from different places. This can be done with a stereo camera which has two lenses and one shutter, with one camera that is shifted to the side or with two similar cameras which are mounted side by side.
There are various ways to view a stereo picture. The most common are the anaglyph and the parallel view.
The view on the right is a parallel. This is the format of the Stereo View Cards that were popular in the early 1900s. It can be viewed with a stereoscope or with a number of updated devices. Many people can free view the pictures.