A Multiplane Background

This is a moving background from my upcoming video. As you can see, the different parts of the background have been placed at different distances from the camera; when the camera zooms in, it gives a sort of 3D effect. This is different from the 3D background scene I featured in an earlier post.
In the days before computers, making a multiplane scene of even a few seconds was an enormous task. The different background elements were painted onto big panes of glass, and these were set at varied distances under the camera, which faced downward. For each camera move, the camera and all the different panes of glass had to be moved in minute increments. When the finished film was projected, it looked as if the camera was moving smoothly. 
There were all sorts of problems. Photographic lights had to be used, and they were super hot! Then, there was always the possibility of the camera being reflected in the panes of glass. Since it was film, if you made a mistake, you had to go back and start all over again. Doing it on a computer is a zillion times easier!