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.
Temple of Venus and Roman Villa, Bay of Verige, Brijuni Islands, Croatia
Off the coast of Istria, Croatia is the Brijuni archipelago, home to ruins of a Roman villa that dates from the 1st century BC and partially inhabited until the 6th century BC. In the year 177 BC, the Illyrians lost their capital of Nesactium to Rome, which brought about lots of changes to the Istrian peninsula. The Roman navy found a safe place to shelter there and wealthy Romans built many luxurious summer residences. Many of the homes were located in the bays of Verige and Dobrika, on mounts Kolci and Gradina, in St. Mikula Bay on Mali Brijun and on the east coast of Vanga.