I have just stumbled across the best source for high quality maps of all sorts of wacky types. Over at Reddit there is a group that aggregates great map images. Unfortunately it has an unfortunate name that makes it educational unfriendly, and might get stuck in your schools filter, so be warned. The group is called Map P*rn, which is the unfortunate part, however, the site is moderated and the content is only full of sexy maps.
Tons of old maps, new maps, fantasy maps, enough to satisfy even the most fanatical map loving humanities teacher. Below are a few public domain examples that I found in a minute of browsing (and another minute to verify the public domain status!)