The Titus Tunnel of Vespasian (Titüs Tüneli) is a Roman engineering marvel, located in Samandağı. It was built as a water channel in the 2nd century.
During the reign of Emperor Vespasian (69-79 AD), the Roman governors of Seleucia Pieria (Samandağ), the port city for Antioch ad Orontes (Antakya), decided to divert a river.
They put Roman legionnaires, sailors and prisoners to work cutting a channel along and through the rock for about 1.4 km (nearly a mile).
Continued under Emperor Titus (79-81), inscriptions tell us it was completed during the reigns of the Antonine emperors decades later.