It sounds totally counter-intuitive that a land locked city would have an amazing aquarium, but its true!
The whales, sharks and dolphin shows are highlights, but they have so many interesting things there, its easy to get lost.
Personally, I thought coming to Seattle and being on the Ocean (basically), it would blow away the Shedd, and its not even a shadow as good. This past spring, I was in Sydney and checked out their aquarium, and while better than Seattle, still not as overwhelming as the Shedd. Although, the Sydney Aquarium had an amazing shark exhibit where you would walk "amongst" them in these underwater tubes.
Anyway, if you are a tourist in Chicago, or going, definitely don't miss the Shedd.
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