Where to see mosaics in Chicago
There are a number of underpass mosaics in Chicago. They are done by the Chicago Public Art Group. Here's an article about them. The mosaics are located at Foster Avenue & Lake Shore Drive, Bryn Mawr and Lake Shore Drive, 57th Street and Lake Shore Drive (near the Museum of Science and Industry), Belmont and Lake Shore Drive.
Marc Chagall mosaic at Exelon Plaza (Monroe and Dearborn).
There are a number of mosaics at CTA stations: Belmont station, Western station (Pink Line), Francisco station (Brown Line), Roosevelt station, Paulina station, Sedgwick station, Fullerton station. Learn more about public art on the CTA & the CTA Arts-In-Transit program. Please add any CTA mosaics I missed!
There are many Chicago mosaics listed on the Public Art in Chicago blog.