The architectural river tour in the summer is great. This tour takes you quite a distance on a ferry on the river through the city. Excellent view of the skyscrapers and excellent tour guides are very thorough in the history of the buildings. Recommend this tour in the summer on a beautiful sunny day.

I definitely agree.

The river boat tour is a GREAT way to see the city and a fun way to take a break from all that walking. If I recall, it's not that expensive either.

It can get pretty crowded down by Navy Pier in the summer, so reservations are highly recommended.