Take the Martian topology (datafiles captured by the Mars Orbiter Laser Alimeter, currently making a height map of the whole planet to within 5 metres), put them into the Terragen scenery generator, then add in a bit of speculation: get these beautiful renderings of a fictional Mars with surface water [via More Like This]. Olympus Mons with an ocean. The coastline of the Deuteronilus Mensae.

(The pattern reminds me of the Atlantic coastline of Long Beach (maps, aerial photos), which I saw flying into New York earlier this year, a wonderful mix of curvy inlets, long spits and fractal islands, so unlike the coasts of anywhere I've seen in the UK.)

Loosely joined griffins everywhere.