Castle of Kefalos is built on the southwestern side of Kos, on the top of a rocky hill to the east of the homonymous village. It is made of small stones and inside it there are water tanks. The castle dates from the Byzantine era. His position, and less the defensive power of his walls, seems to have given value to the castle and helped to resist hostile victories. Today, there are few remains of the castle and the visitor can enjoy the panoramic view of the bay of Kefalos. At the time of the Knights was one of the three great castles of the island.