Downtown Chicago is the most beautiful downtown in the USA. Just walk Michigan Avenue. I stayed at Club Quarters at Wacker and Michigan. I walked across the Chicago River and a few blocks and the shopping began. Nordstrom and Bloomingdales are not architecturally interesting, but its the inside that matters.
Walk back across the river and a couple of blocks and you are at Millenium Park and a block or two from the South Lakeshore Drive.
There is the famous Cloud, which is always different depending on the weather and the people interacting with the sculpture.
These are new sculptures from my last visit to Chicago. People have already created ways to interact with them.
Across the street from Millenium Park is the Art Institute of Chicago. I have spent many hours on previous trips. This time I only visited the bookstore (a terrific bookstore). The walk along the park continues all the way to Field Museum and Soldier Field.
The park goes on. I have never walked past Soldier Field. There is a city bike rental program if you want to find a quick way to get back.