All around the Cydonia area the mesas form creepy shapes that do a fine job of imitating alien fortresses, monuments, plazas, spaceports, and a deep cavern entrance that seems to run under the plateau itself. (see my scrapbook and click on image to explore, or to the ESA site and see even more). It would take Geiger about 30 seconds of pen work to bring it all to life enough to scare the pants off H.P. Lovecraft.
Mars has some truly alien geography. If we humans ever get there and start poking around in heat vents and cave areas where water can exist wet, I bet we find some living stuff we have not seen before....