At a short distance from the of Relief of Mithras Tauroctonos (Mithras the Bull-slayer), on the location "Stithoma" (Gradtiste), NE of the settlement of Thermes, the ruins of a fortress enclosure are preserved. It was built during the Imperial period but remained in use during the Byzantine period as well, since it provided control of the riverside area.   

Although it is not organized, it has been declared an archeological site by the Ministry of Culture.