Katedral Sveti Duje - © Matt Field/Time Out
Once the site of Diocletian's mausoleum, and still guarded by a granite sphinx from ancient Egypt, this octagonal building was converted into a church by the refugees from Salona. Through the Middle Ages, it was given finely carved doors, an equally beautiful pulpit and eventually a belltower offering a panoramic view of the palace. The climb (5kn) can be quite dizzying, so only try it if you have a head for heights. The crypt contains rare ecclesiastical treasures dating back to the eighth century.