Castle of Gardiki

Gardiki Castle is a 13th-century Byzantine castle on the southwestern coast of Corfu and the only surviving medieval fortress on the southern part of the island. It was built by a ruler of the Despotate of Epirus, and was one of three castles which defended the island before the Venetian era. The three castles formed a defensive triangle, with Gardiki guarding the island's south, Kassiopi Castle the northeast and Angelokastro the northwest

Source: Wikipedia