Satellite view of Istanbul, Turkey, on the Bosphorus Strait, encompassing the natural harbor known as the Golden Horn, in the northwest of the country. It extends both on the European (Thrace) and on the Asian (Anatolia) sides of the Bosphorus, and is thereby the only metropolis in the world that is situated on two continents. To the north lies the Black Sea, and to the south the Marmara Sea.