Diocletian’s Palace, located in Split, Croatia, is a remarkable historical site built at the end of the 3rd century AD as a retirement residence for the Roman Emperor Diocletian. This UNESCO World Heritage site is unique for its blend of ancient Roman architecture and modern life, as it forms about half of Split’s old town. Visitors can explore its well-preserved ruins, including the Peristyle Square, the Cathedral of Saint Domnius, and the ancient cellars. The palace also houses shops, restaurants, and apartments.