In the ancient naval station of Thassos
In the port of Thassos, east of the city, traces of the ancient 'enclosed' military harbor of Thassos can be seen below the surface of the water. This is the protected ancient naval base where the war triremes were kept during the winter months. This "closed" port was the continuation of the land walls of the city. It was built at the beginning of the 5th century BC.
The inhabitants of Thassos paid special attention to the coastal fortification of their city. Later additions and circular towers were built at the end of the 4th century BC, while during the Early Christian period (4th -7th century AD) they transported the entrance of the port. The ancient naval base is a declared marine archeological site and is one of the first of its kind.