To see this photo in realistic three-dimensional depth, position yourself directly in front of the image, about 12 inches away. Use reading glasses if needed to see the images clearly. (You may need to resize your screen so that the image is no wider than 5 inches). Stare at the image, but unfocus your eyes, or pretend to focus on something far away, as if it were 50 feet behind your screen. As you relax your eyes you should begin to see the two panes of this image gradually becoming three panes (look for a third black arch forming in between the other two arches at the top). Once you clearly see three panes, refocus on the center one. It will appear in three dimensions, almost magically, mimicking how our eyes actually would see the subject on site.
Anyone can take 3-D photographs, with any camera, including cell phones. The basic principle is that our eyes see depth because of binocular vision, or seeing our surroundings with two eyes. To take a picture like the one displayed here simply shoot a photo of your subject, making sure nothing is moving in the scene. Then move your camera approximately 2.5" directly to the right (or left) and re-shoot the subject, trying to get as close as possible to the same composition or framing. If something is moving, such as people or traffic, the second photo won't be the same as the first one, so the process won't work. The last step is to use software to place the photos directly side-by-side. Make sure they are correctly positioned: the image on the left should be what the left eye would see, and the image on the right what the right eye would see (it sometimes takes some testing to figure this out). Vertical pictures work better than horizontal ones, since they are narrower relative to the entire overall composition, which makes it easier for the eyes to switch into parallex mode.