Can someone point me to 3D model of surface of the land and ocean floor of the Earth, or a grayscale elevation map so I could make my own 3D model from it. I was curious - I wanted to play a bit with such "flat" (rectangular i.e. not spherical) 3D model of Earth's relief by placing a flat surface (that is: ocean surface) parallel to it intersecting with relief features at different levels so I would see how would Earth map look like with different ocean levels. (I mean - imagine: new islands, new continents and other features - like some other planet!) If someone already made that - I would like to see so give me some link - if not - give me material (grayscale-value elevation map in high enough resolution, but not too large) and I'll make it - no problem!