Built by Roman emperor Diocletian in the 4th century, the palace is a massive complex around which the city of Split has developed. It's important to realize that Split's old town is synonymous with what is considered to be the palace, where modern residences share space with preserved bell towers, a mausoleum, cafes, and eateries on what used to be the palace grounds. And despite the inevitable tourist trappings, the sight of local kids booting soccer balls around the bases of ancient statues and travelers crowding millennia-old cafes still has a way of playing on the imagination.
To provide some historic context, visit the substructure of the palace for a glimpse at original floor plans and how things used to be for a cost of 15 Kuna (about 3 US dollars).
Note:You might be pleased to hear that, in spite of the obvious modernization, there are continued efforts made at maintaining the authenticity and integrity of the palace ruins, and efforts to build shopping malls and other tourist-related amenities have been condemned. Good for you, Split. Good for you.