Roman Amphitheater at Salona, Croatia
Salona, was founded by Illyrians, followed by Greeks and then Romans who made Salona the capital of the Roman province of Dalmatia. The 2nd century AD amphitheater at Salona was designed to hold eighteen to twenty thousand people. One unique feature, not found in other Roman amphitheaters, is the underground channels. There are many theories about their use but the most commonly accepted explanation is that the channels were used to perform mock naval battles.
Salona had a mint that was connected with the mint in Sirmium and silver mines in the Dinaric Alps through Via Argentaria. When the Roman Emperor Diocletian retired, he erected a monumental palace nearby. The city was largely destroyed by the Avars and Slavs in the 6th and 7th centuries. The ruins of Salona are located on the Dalmatian coast of modern Croatia.