Mars City is a megacity containing over 18 million (registered and SINned) inhabitants. It has been growing steadily since it’s founding, with a constant influx of ex-Earth dwellers looking for new opportunites, a fresh start, or just a change of scenery (the stars look great without the magnetoshpere). The city initially started with a wide footprint based around the corp towers in a grid system. The city was quickly flooded with refugees, exiles, and others fleeing Earth for a variety of reasons during the initial batch of immigration. It was easy to recruit amongst these communities as a number of governments and corps were offering to cover travel costs, in return for 3 to 10 year contracts, depending on the sponsoring entity. This had the effect of creating a system of indentured servitude very beneficial to corps looking for cheap labor, as well as the directors of the terraforming and infrastructure building programs. However, once Mars City was constructed, it was decided by the rich and powerful that they didn’t want to encounter all the lower classes in their new home. They still needed these lower classes for cheap labor, of course. The corps didn’t want to move their towers, so an elegant solution was arranged: the bottoms of all the towers were sealed off and a second city was built, suspended directly overhead. The middle and upper classes could live free from fear, filth, and guilt in the shining, clean and well-policed upper city, while the laborers, refugees and poor were consigned to the cold, artificial light of the undercity. Not all of the undercity is slums, by any means. A variety of criminal enterprises (ranging from organized crime to street gangs) control the various sectors, divided by the support struts erected to support the metropolis above. Turf warfare is consistent, if not constant, but most undercity denizens manage to survive one way or another, whether scavenging for supplies in the cities dumps, working in uppercity shops or as low level wageslaves, or, for a select few, running the shadows.

Sewage is heavily reprocessed to extract reusable nutrients, especially water, as this is the most limited resource on Mars. Diet consists primarily of soy, algae, kelp, and krill based foods, as well as vitamin and protein pills/shakes/injections. More standard Earth plants, as well as vat-grown animal flesh, are also available to those who can afford them. Actual animal flesh is a luxury, and Earth imports of this (especially what limited non-krill seafood is still available) as well as some of the more rare forms of produce are extremely expensive and hard to come by for most Martians.