You may know about this already...
One of the most important aspects in determining how a population center thrives is how it aligns with patterns of traffic as shaped by the natural landforms.
Orbis allows us to study this phenomenon in amazing detail, with a look at the ancient world from the perspective of travel time and related phenomena.

ORBIS

I for one would like to know what the underlying map engine is. I'd love to play with is sans their data and overlays.