The Bardo Museum is the national archeological museum of Tunisia. It has the arrowheads and pottery and statues you find at most such museums, but what it really has is mosaics. Almost every room's walls, and in some cases floors, are covered with them. They're enormous, very well preserved, and in most cases come from the various Roman cities that were built in what is now Tunisia. The downside of this is that when you go to the original sites you see a flat square hole in the ground.