The island's most characteristic monument is the Castle of Chora! The castle, or "Fortezza," was built in the 13th century when Kythera was ruled by the Venetians. The "Eye of Crete," as it was also called due to its strategic location, allowing ships to observe three seas simultaneously—the Ionian, the Aegean, and the Cretan—was built at various stages of the island's history, but the largest and most important part, including the facade, was built in 1503 by the Venetians, who subsequently repaired and reconstructed it. At the entrance to the castle, you can see the tunnel, or "fossa"! On this front wall, the Venetian coat of arms of the Lion of St. Mark once stood, but it was destroyed by the French in 1797, along with the book of nobility and the coats of arms. To the left of the castle entrance, you can see the prison, and a little further up, on the right side of the southwestern part, the huge Venetian reservoir with domes and arches.