Kos is full of reminders of classical Greece, and of the Knights of St John, who held the island for two centuries in the late Middle Ages. Their impressive fortress remains, enclosed by two sets of walls with massive towers at the corners. Below is a colorful and charming town clad in palm-lined walks, white colonnaded houses, and gardens of red hibiscus. On a terraced hillside is a sanctuary consecrated to Asclepius, a healer and son of Apollo, but dedicated to Hippocrates, the father of medicine, born here about 460 BC. It was a place of worship, but also a medical facility staffed by priest healers.