A teacher who uses vectary gave me a link to a website which creates .stl files from any map location http://jthatch.com/Terrain2STL/
I choose the famous mountain Matterhorn in the Swiss Alps. Once I imported the .stl file which was just drag and drop. I fixed some holes, one on the bottom and two smaller ones, they were highlighted with red lines, so I used the "cap open boundries" tool. I made also a "negative" form by rotating the mountain 180 degree and extruded the walls to add thickness. Added some legz to to keep it in level.
Thanks David Carter for the tip also for the positive feedback.
What is your favourite mountain, volacno, island? What would you do with a topo-model?