Densely populated, this area includes the cities of Istanbul and Edirne. The Bosphorus, which links the Sea of Marmara and the Black Sea, is about twenty-five kilometers long and averages 1.5 kilometers in width but narrows in places to less than 1,000 meters. There are two suspension bridges over the Bosphorus, both its Asian and European banks rise steeply from the water and form a succession of cliffs, coves, and nearly landlocked bays. Most of the shores are densely wooded and are marked by numerous small towns and villages. The Dardanelles (ancient Hellespont) strait, which links the Sea of Marmara (ancient Propontis) and the Aegean Sea, is approximately forty kilometers long and increases in width toward the south. Unlike the Bosphorus, the Dardanelles has fewer settlements along its shores. The Saros Bay is located near the Gallipoli peninsula and is disliked because of dirty beaches. It is a favourite spot among scuba divers for the richness of its underwater fauna and is becoming increasingly popular due to its vicinity to Istanbul.