Bosporus a strait connecting the Black Sea with the Sea of Marmara, and separating Europe from the Anatolian peninsula of western Asia; Istanbul (originally Byzantium and then Constantinople) is located at its south end. Its name, meaning ‘cow's passage’, is said to derive from the legend that Io crossed it in her flight from Hera's vengeance.

Bosporus (Karadeniz Bogazi) Narrow strait joining the Sea of Marmara with the Black Sea, and separating European and Asiatic Turkey. It is an important strategic and commercial waterway, controlled by the Turks since 1452, and refortified after the Montreux Convention of 1936. Length: 30km (19mi).