The remnants of Roman Diocaesarea sit within the village of Uzuncaburç, 30km northeast of Silifke. Originally this was the Hellenistic city of Olba, home to a zealous cult that worshipped Zeus Olbius.
The impressive Temple of Zeus Olbius, with two dozen erect columns, lies to the left of the one-time colonnaded street. Beside the temple are various sarcophagi bearing reliefs. Other important Roman structures include a nymphaeum (2nd century AD), an arched city gate and the Temple of Tyche (1st century AD).
Just before the massive monumental arch serving as the entrance to the main site is a small 2500-seat Roman theatre built under Marcus Aurelius in the 2nd century AD.
To view a Hellenistic structure built before the Romans sacked Olba, head north through the village, where you'll pass a massive, five-storey watch tower with a Roman road behind it. Another 600m down into the valley leads to a long, roadside necropolis of rock-cut tombs and more sarcophagi.
On the road to Uzuncaburç, 8km out of Silifke at Demircili – ancient Imbriogon – you'll pass several superb examples of Roman monumental tombs that resemble houses.