Back in history, before they invented 3-D glasses, people used to use stereoscopic photography for three-dimensional effects. This is a stereograph from 1898 that I converted to red/cyan anaglyph.

The Library of Congress has thousands of these old stereographs available for your perusal online, and they are all in the public domain, so you can use them however you want. To see them, just go to the Prints and Photographs search page, and search for "stereograph."