These are some fascinating three dimensional images of Japan before world war II. One popular thing at the dawn of photography was a little viewer called a stereoscope. People would take two photographs at the same time, and then you would be able to see the scene in 3d.
Somebody had the bright idea of just creating animated gif images with these old photos - where the picture switches back and forth between the two. This effectively gives you a conception of 3 dimensions, although it is a bit dizzying at first.