The NYC and volcano stuff is boring, now. Here are some US regions you can emulate.
Driftless Area/Ocooch Mts (central and southwestern WI, SE MN and NE IA -
hilly [up to 18:%] / rolling)
The Kettle Moraine (SE WI - rolling up w/ some 10-12 %'ers)
The continental divide (northern WI - same as above)
The Uinta and Wasatch Mtns Utah
Get the programmers out with their drones and get drawing.