The Destroyed Lands map - create a regional map depicting a civilization destroying cataclysm of epic proportions, a sort of post apocalyptic map, with the major feature showing the remnants of the great cataclysm.
Decide on a type of destruction that can be depicted on a map, something that complete alters the landscape from what it was before. It could be the crater left by a comet strike, a new coastline after an earthquake dropped California into the Pacific, the fast rise of a great volatile volcano in the middle of a city, or arcane destruction (1 M HD Fireball, anyone?), anything else you can come up with.
Of course, you can also depict survivalist camps or whatever else you want, the main goal is to show a world in its aftermath of destruction.
Fantasy, modern, futuristic doesn't matter, show me a map of destroyed lands, that's what I'd like to see!