Your comment about Chicago decaying made me think of the Dresden Files, & how Harry remarks that Chicago is built on Chicago, bc the swampy ground means everything is slowly sinking. How true is this?
100% true. Chicago is built on a swamp, predominantly between a river and a lake. Supposedly “Chi ka gua” means “swamp of the stinking onions” in a local indigenous language (I thiiiiiink the Potawatomi but I could be mistaken, don’t quote me).
Prior to the introduction of the grillage in Chicago architecture – again don’t quote me but I believe a Chicago architect invented the grillage to deal with Chicago’s unique challenges – high-rise (for the time) buildings would be constructed with a built-in “sink” measurement, usually between eight and eighteen inches. Ground-level doors were placed slightly above ground level with the expectation that over the course of a year or two, the building would sink as it settled into the swampy soil. If you go to the Rookery Building on a Wednesday and take the Chicago Architectural Society tour they will take you into the service corridors of the building, which is pre-grillage, and you can see the frankly fascinating ways in which the floor of the building warped as it settled.
A grillage is a series of steel beams layered across one another horizontally, which works a little like a raft, allowing a building to “float” on Chicago’s swampy soil; most buildings from the last century, including the one I live in, have a grillage underneath them. Someday a big earthquake is going to hit and it’s going to look awesome from somewhere other than inside Chicago.
Additionally, the “Streeterville” neighborhood is named for a pirate and all-round asshole named Streeter who basically salvaged and dumped any goddamn rubbish he could find around a sandbar in the lake until he had literally extended Chicago out into the lake in a large enough swath to create an entirely new neighborhood, which is now one of the most expensive areas to live in. That part of Chicago is very literally built on Chicago, as I believe one of the sources of his rubbish was haul-off from the Great Chicago Fire.
And to conclude there are parts of Chicago, just south of Streeterville, where factories creating very toxic byproducts dumped industrial waste, so part of Chicago is literally radioactive and you can’t build there without extensive soil studies being done to make sure you won’t kick up the radioactive dust and poison everything in the immediate vicinity.
Chicago’s municipal motto, by the way, is “Urbs in Horto” which translates as “The City in the Garden”.