Calamari for dinner tonight, Kos Island, Greece. Kos, one of Greece’s Dodecanese Islands, is known for its abundant sandy beaches. It’s also rich with Greek and Roman antiquities, particularly in and around busy Kos Town. This harbor city is dominated by the 15th-century Castle of the Knights fortress. It’s also home to the Kos Archaeological Museum, the Ancient Agora ruins, and the 3rd-century Casa Romana villa with its lavish mosaics.