This image of Chicago and 16 miles (26 km) of the Lake Michigan shoreline was taken from the International Space Station. It shows how natural features control the growth of the city. Chicago's center--known as the Loop--lies at the mouth of the Chicago River, reflecting a time when this was the earliest settlement at a point where lake and river traffic converged. Navy Pier was built in 1916 at this transportation node primarily as a cargo facility for lake freighters. The city center still occupies the same location nearly two hundred years later.
Modern highways (I-94 and I-55) prominently are aligned toward the city center, following older transportation routes that ran along the banks of the North and South Branches of the Chicago River-that are still used by barge traffic. Railroads also converge on the city center. Residential and business land uses are competing with the transport functions. For example, Meigs Field was the small downtown airport located on Northerly Island that was bulldozed in 2003 to make way for a city waterfront park.
The city center is distinctly darker as seen from orbit because high rise buildings in the Loop cast much more shadow than low buildings in the surrounding neighborhoods.