I’ve been experimenting with 3D pictures for a while now. The idea is, the left eye and the right eye see a scenery from 2 different angles, so if you take a photo, move the camera several cm to one side, and take another photo, you can combine them to have a 3D picture. One way to view such a picture is to have the image for the right eye on the left side, the image for the left eye on the right side, and to get the 3 dimensional effect, you have to cross your eyes. Here is an explanation with pictures, and a video tutorial on YouTube.
Once you can get it, enjoy some 3D!