High on a rock above the sea on the northwest end of Kythnos is Kastro Orias, the capital of the island during Byzantine and Venetian rule. Said to be impregnable the town is in ruins now but the ancient walls and streets are still in evidence and there are two of the 100 churches that used to stand here, that have been restored. You can reach Kastro Orias, also known as Kefalikastro, by car or on foot.
