Tios Ancient City Tios, also known as Tieion, was an ancient Ionian colony situated on the western coast of the Black Sea in Zonguldak province. Its history dates back to around 700 BC when it was founded by Milesian settlers. Over the years, it was occupied by Persians, Romans, Genovese traders, and Turkish people. Despite the city's long history, limited information is available about its archaeological past. Some remains, such as coastal defensive walls, an aqueduct, a theatre, a defensive tower, and the port with its breakwaters, are still visible, but they date only from the Roman period. The acropolis of Tios is located in the northeast of Filyos on a hill overlooking the village. Although its defensive walls still exist, only their foundations are visible, and more research is needed to uncover their original architectural form. Within the acropolis, a partially destroyed stone building from a previous civilization can still be seen. A Roman period theatre is also located near the entrance to Filyos from the main road. The Amphitheatre, built on a small hillside, was constructed using stones from the site itself, and much of its original material was repurposed in other buildings. However, one section of it still remains standing. Another structure that has been identified as having defensive functions is located 100 meters west of the theatre and about 200 meters from the edge of town. Today, there are several ruins scattered throughout the district, including a castle, an open-air theatre, an underground city, aqueducts, and an ancient pier.