I've been having trouble finding heightmap data from the real world, so I stubbed this page at the game development wiki. I've added a USGS link I've found so maybe someone will consider that helpful. And if you know of some more places to get them then feel free to add a link. http://wiki.rednek.net/index.pl?RealWorldElevationMaps

make a google for 'digital elevation model' or dem etc and you may find some usefull stuff. ok but i will post some of the links i've found (beware there is more than one dem format afaik):

30arc-sec world dem's: Teh World in 1km Rezoluzion
haway, idaho and washington 10m dems: some 2gb or more if you download all of the washington dems :p (*cought* WinHTTrack website copier is a must *cought*)
terrainmap.com: site with links infos etc, very usefull
www.geographynetwork.com: havent checked this site, but i think it has some free dem's
lake tahoe dem: useless but a good start to test your dem loader...


i had some more links, one was to a different 30arcsec set of the world and some other stuff, but somehow i lost them. the best i found for europa was the 1km dem's


T2k