Here are ten shots of Chicago from viewpoints ranging from 40 miles to 2 miles away:
New Buffalo, MI (40 miles from skyline)
Michigan City, IN (33 miles from skyline)
Beverly Shores, IN (30 miles from skyline)
Indiana Dunes, IN (28 miles from skyline)
Burns Harbor, IN (26 miles from skyline)
Gary, IN (21 miles from skyline)
Whiting, IN (15 miles from skyline)
Rainbow Park, IL (8 miles from skyline)
Harold Washington Park, IL (6 miles from skyline)
31st St Harbor, IL (2 miles from skyline)
Question is, what's hiding the lower part of the city?
Curvature? Perspective? Haze? Waves?