When I was a kid I was dragged through more National Park visitor centers than I can remember. For me the highlight was the always the miniature model of whatever park it was. By exploring that model you could experience the landscape as if you are a bird (or Superman) and able to fly around. Standing in Yosemite valley looking up at Half Dome is amazing, but you only see it from one angle. The 3d model in the visitor center reveals so much more.
When I got into 3d printing one of the first "killer apps" I discovered was printing 3d maps. Everyone asks me what a 3d printer is good for. Well here is a great use. With a little time and some free or inexpensive software you can make your own 3d model just like the cool one in the visitor center. What's more you can make such a model of anywhere in the world. And depending on the data available you can sometimes make a model much more accurate than the one in the visitor center. For instance my model of Yosemite valley is so accurate that you can see individual trees.
You aren't limited to anywhere in this world, with a little digging you can find data for the Moon and Mars as well.
If you want to see an exact step by step walk through of this process you can watch either of my two videos linked above.
I made my first 3d terrain models following the instructions given by Gregor Luetolf. His techniques work well and I still use some of the same software, but I have made some improvements which I will detail here.
The basic process is as follows:
1 Get digital elevation data for the area you wish to model. You will typically download that data as a GeoTiff file.
2 If necessary, crop the section of interest from the larger dataset.
3 Convert that data to a DEM file.
4 Make a 3d model based on the data.
5 Print and enjoy.