Archaeologists discovered a tower near the Kastritsi fortress, once part of ancient Evksinograd, in the Varna region.
The square foundations of the tower measure eight metres in width Valentin Pletnyov, director of Varna Regional History Museum told Focus news agency.
The tower is supported by a massive fortress wall, which in the past probably protected the harbour, Pletnyov said. The tower was constructed as a place where refugees and soldiers could flee if the fortress was taken. Usually such towers are the most solid constructions, often used as prisons.
During the excavations archaeologists also discovered coins from the Antiquity and the Middle Ages, weapons, bronze and copper lamps and decorated ceramics. According to plans archaeologists would continue working until August 20.
The team working on the site includes experts from the Varna History Museum and students from Varna Free University.