A museum with a difference, this religious gem is on the 2nd floor of the Archiepiscopal Palace. It hides two not-to-be-missed exhibits: an exquisite ivory throne carved for Emperor Maximilian by Byzantium craftsmen in the 6th century (the surviving detail is astounding); and the stunning collection of mosaics in the 5th-century chapel of San Andrea, which has been cleverly incorporated into the museum's plush modern interior.