I found this picture via Digg
. It's now my new desktop picture (replacing the very first image taken on the surface of Mars by Viking I). I find the picture incredibly cool, and can't help but try and analyze what it represents.
From the way the horizon curves upward, and the generally tubular view, the city is clearly built on the inside surface of a toroid structure. The only reason that could possibly make sense is if it were built in space, either as some sort of free-floating space station, or some sort of habitation ring attached to a ship of some kind, and spun to create artificial gravity. It could, I suppose, also be some sort of variation on a Dyson shell
, as in Larry Niven's Ringworld
The tube-looking thing running along the ceiling, then, would most likely be some sort of high speed transportation system that takes advantage of the lower gravity that exists closer to the axis of rotation. Although that then begs the question of why they bothered to have boats in the river. Perhaps it's not meant for every day transportation, but is instead intended as a sort of 'airport shuttle' to take people to other parts of the ship or to an unspun spacecraft docking area.
Very cool. There's so much detail in this picture I'm sure I'll come up with more, but for right now, it's way too early on a Saturday morning to be putting this much thought into a picture...