Beautiful medieval buildings, including some bridges and an exquisite catholic cathedral (I'm not easily impressed by churches, but this one has as beautiful an interior in its own way as the one in Salisbury, UK).
Definitely worth a detour, or even a half-day trip (we were staying in Toulouse and did Carcassonne and Albi in one day, by car; while Carcassonne is the bigger attraction, I liked Albi a lot better).
Expect to have to walk to the sights; there is no place to park (nor, in many cases, to drive) near them.
