Istanbul is a city divided. The Bosphorus—the 31-km-long (17-mile-long) waterway joining the Black Sea to the Sea of Marmara—separates the European side of the city from the Asian side. The European side is itself divided by the Golden Horn, an 8-km-long (5-mile-long) inlet that lies between historic Sultanahmet to the south and the new town, known as Beyoğlu, to the north. In Beyoğlu, the 14th-century Galata Tower dominates the hillside that rises north of the Golden Horn; just beyond, high-rise hotels and other landmarks of the modern city radiate out from Taksim Square, not far above the Bosphorus-side neighborhood of Beşiktaş. To the north, European suburbs line the western shore of the Bosphorus. The Asian suburbs are on the eastern shore.