I'm looking for a recognisable part of the world which is donut shaped for a game design. Specifically I'm looking for a ring-shape with mostly consistent width borders around the central hole. It would also help if there's a reasonably consistent scattering of cities, towns, villages, hamlets or whatever around the central hole and across the width of the border. Candidates might be a state or political region surrouding a lake, sea or crater; an atol of unusually large size (ie large enough to support at least a dozen+ significant habitation sites; or even Hal Clement's "Mission into Gravity" world (assuming that the high-G regions could be treated as a hole).
I don't particularly care where in the world it is. It could even be from a work of fiction if the fictional work is reasonably well known. Larry Niven's Ringworld is thus a candiate but isn't ideal due to the land masses being so broken up by seas. Clement's MiG world is just poorly mapped. My players prefer at least a pretense of thematic consistency and I know exactly what I want to do with the game, I just need an arbitrary location theme to bolt it on to. My best idea so far is to just pick a ring of land around Lake Baikal in Russia, and that's not much of an idea (fascinating tho Lake Baikal is).
Any more interesting ideas?
That would work except for the cities and other habitations requirement. This is a pick-up-and-deliver game among locations. Yeah, I could do the whole expedition supply points thing, but that jells with an otherwise railroading base poorly.