Tios (Filyos) Archaeological Site

Tios was founded just east of the point where the ancient Billaios, today the Filyos, flows into the Black Sea. It stood on the coastal route between eastern Bithynia and western Paphlagonia, and today its ruins lie in the town of Filyos in Zonguldak province's Çaycuma district.

In antiquity the city was surrounded by the Black Sea (Pontos Euxeinos) to the north, Herakleia Pontike (Karadeniz Ereğlisi) to the west, Amastris (Amasra) to the east, and by Hadrianopolis, Krateia-Flaviopolis and Claudiopolis inland.

It is known as the only Greek-Roman city on the Black Sea coast that has not been buried beneath modern settlement or under alluvium, sand and mud. That makes Tios unusually valuable for anyone interested in how a coastal city of this region was laid out and grew.