Classrooms of different nationalities is basically what Cathedral of Learning is, if you go pass the tour times and want to explore on your own.
I love the concept of how you get to see how different people are educated in different countries. You can walk into the classrooms, instead of being blocked at the door like every other museum would do. You can sit down at the chairs/benches, write on the blackboard, and get really close to the decor.
It's a small place, I spent less than an hour here.