Six regions, six different-looking worlds

What actually varies by region

Three things do most of the work. Building era: a city that grew before the car has an irregular core, and one that grew after has a grid. Density profile: some regions build tall in one place, some build medium-rise everywhere, some do both. Landscape: desert, tropics, temperate coast and mountain valley are all distinguishable from above even before you look at the buildings.