Embraced by beautiful beaches and thousands of years of history, Kos is a tiny but mighty Dodecanese island in the wide Aegean Sea. The charming harbor town is dominated by the 15th-century Castle of the Knights, steps from the famous Tree of Hippocrates where the philosopher and native son is said to have taught. Just outside of town, further tribute to the Father of Medicine is found at the ruins of the Asklepieion, a center of healing dating to the 3rd century BC. In the town center, the Ancient Agora includes remnants of a temple and shrine, and the 3rd-century villa of Casa Romana features elaborate mosaics. With basilica ruins on one end, Agios Stefanos beach combines island history with a lovely day of snorkeling in crystalline waters. Back on land, take a stroll through Eleftherios Square to shop for leather goods, ceramics or jewelry before stopping into local café for fresh seafood and a traditional Greek salad.