You can easily lose yourself in an afternoon here. I'm ashamed to say that it's taken me many, many years as a Pittsburgh area resident to actually make a visit. If you like architecture, art history, or learning about different countries and cultures, the Cathedral of Learning is the place for you because of the incredible Nationality Rooms. (It almost makes me wish I went to Pitt!) One of the best times to go is when school is out over the summer, because those rooms are functioning classrooms and meeting spaces during the academic year. The newer rooms built in and after the late 1980s have a recorded narration that you can flip a switch in the room to listen to, but in the older rooms on the 1st floor, be sure to go to the gift shop and rent an audio guide. You'll get some more context and information about the decor that way.