I'm going to be in Chicago for a few days next month. I assume that there is absolutely nothing interesting to do in Chicago, but on the slight chance that I'm wrong I'd like to hear your suggestions about sites and activities. When I have a chance to look around a city, I look for a bit of the "flavor" of that city -- food, culture, places people hang out, etc. I'm a science/technology geek, my camera is always on the lookout for interesting photo ops, I don't mind museums, and on this trip I have a particular interest in architecture. That's because I'll be siteseeing with an architect friend who hasn't been to Chicago before. This will be my third trip there, but the first when I'll have more than a day to play tourist. What shouldn't I miss?