A normal photograph is just one picture - a one-eyed view which does not show distances. You can as easily take two pictures, a left-eye picture and a right-eye picture. Lay this stereo-pair side by side, see the left-eye picture with the left eye and the right-eye picture with the right eye, and a usual binocular (two-eyed) impression is obtained in all its glory.
This webpage is to show how to see stereo-pairs. Anything essentially three-dimensional is best viewed in stereo. Examples are given here. They are easy to take; they provide a faithful record of three-dimensional details and cross-eye viewing is instantaneous. There are many potential applications.
Most people are capable of seeing stereo-pair pictures without the aid of a stereoscope. No special abilities are required. Stereo-pair pictures allow one the excitement of seeing the hitherto unseen: -
Newspapers and journals and bookshops should regularly show cross-eye stereo-pairs, and children should compare their favorite stereo cards. Here are great commercial opportunities.