Diocletian's Palace is an ancient palace built for the Roman emperor Diocletian at the end of the third century AD, which today forms about half of the old town of Split, Croatia. While it is referred to as a "palace" because of its intended use as the retirement residence of Diocletian, the term can be misleading as the structure is massive and more resembles a large fortress: about half of it was for Diocletian's personal use, and the rest housed the military garrison.
The complex was built on a peninsula six kilometres southwest from Salona, the former capital of Dalmatia, one of the largest cities of the late empire with 60,000 people and the birthplace of Diocletian. The terrain around Salona slopes gently seaward and is typical karst, consisting of low limestone ridges running east to west with marl in the clefts between them. Today the remains of the palace are part of the historic core of Split, which in 1979 was listed by UNESCO as a World Heritage Site.
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Wikipedia https://en.wikipedia.org/wiki/Diocletian's_Palace
Official website http://www.diocletianspalace.org/
More information on UNESCO's website http://whc.unesco.org/en/list/97
Address 8 Krešimirova, Split 21000, Croatia
Coordinates 43°30'30.091" N 16°26'24.659" E