I actually remembered to get some pictures while I was visiting Chicago last weekend and this one in particular turned out a lot better than I had hoped.
It was a generally cloudy day and we got lucky enough that the clouds had risen enough that the view from the Hancock Tower observation deck was actually pretty decent. The “smoke” in the foreground of this picture is actually water vapor from an unpictured building’s rooftop HVAC system. 
You can see the rest of the set here.
