The natural surroundings of Chicago obviously have played a large role in allowing it's Economy to thrive. (well maybe not recently) Are there any Natural reasons behind it's growth? Other than the obvious Chicago river, meatpacking industry, and grain.
Chicago had two great geographic advantages:
It was one of the most convenient points to transfer between the Great Lakes and the Mississippi watersheds. Originally this was via portaging canoes, but eventually, canals were engineered, so Chicago became a hub for waterborne transport between these two great basins.
When railroads started to supplement or replace waterborne transport, Chicago, at the southern point of the Great Lakes, was an essential point for all rail lines wanting to go either north east or north west of Lake Michigan. It was also a point where rail transport could tranship with water transport. So, Chicago became a great rail hub.
How do we define nature? When do human systems and the way they reshape and build a second nature around natural systems become the real 'natural force'? How did Chicago pioneer the extraction, marketing, and reordering of the natural world, all the while building a bigger Chicago? If you're interested in this topic, there is really only one thing you should do: Read Nature's Metropolis by William Cronon. Its the classic on how cities shape the environment and are shaped by them and its all about Chicago