The second-largest art museum in the country, the Art Institute houses treasures and masterpieces from around the globe, including a fabulous selection of both impressionist and post-impressionist paintings. The Modern Wing dazzles with natural light, and hangs Picassos and Mirós on its 3rd floor.
Allow two hours to browse the museum's highlights; art buffs should allocate much longer. Ask at the front desk about free talks and tours once you're inside. Note that the 3rd-floor contemporary sculpture garden is always free. It has great city views and connects to Millennium Park via the mod, pedestrian-only Nichols Bridgeway.