Free Admission Wednesday from 10am to 5pm at Chicago Cultural Center - see INFO below. Incorporated as a city in 1837, Chicago was ideally situated to take advantage of the trading possibilities created by the nations westward expansion. The completion of the Illinois Michigan Canal in 1848 created a water link between the Great Lakes and the Mississippi River, but the canal was soon rendered obsolete by railroads. Today, 50 percent of U.S. rail freight continues to pass through Chicago, even as the city has become the nations busiest aviation center, thanks to OHare and Midway International airports. More Info below.