Tags: Military Structure.
Ktenia (Bulgarian: Ктения Greek: Κτένια) is a ruined Roman and medieval fortress situated 2.1 km to the north of the village of Lozarevo in Sungurlare Municipality Burgas Province south-eastern Bulgaria. In the Middle Ages Ktenia often changed hands between Bulgaria and Byzantium.The ruins of the fortress lie northeast of the town of Sungurlare in the Grebenets section of the Eastern Balkan Mountains.