This is a 22 piece 3d topo map of Yosemite Valley which I showed at the San Mateo MakerFaire. Each piece is a 2km square chunk. The STL files are scaled to 100mm square making the overall scale 1:20,000. The individual models are detailed enough that they could be printed at at least double their size without getting "voxelated". I tend to print small sections to avoid the distortion which sometimes comes with larger prints.
There is a diagram showing where each piece fits so you could print only your favorite landmarks, or start with Half Dome and work your way down the valley like I did.
The final model is more than 2 feet long (0.7m to be exact). There is no real reason to stop here except that the high resolution Lidar survey data goes no further. The data comes from http://opentopo.sdsc.edu/ where you can freely download amazingly detailed datasets from around the world.
We talked about this thing and a whole lot more on the 3D Printing Today podcast available on iTunes, Stitcher radio or direct from the source at http://threedprintingtoday.libsyn.com/
The technique for making these models is detailed in my youtube video https://www.youtube.com/watch?v=t4-ICkvyJv0.