The Sea of Marmara
Marmara, Sea of, a sea that lies between the European and Asiatic parts of Turkey. It is about 50 miles (80 km) wide and 170 miles (270 km) long and covers 4,300 square miles (11,100 km2). The Dardanelles strait leads southwestward to the Aegean Sea; the Bosporus strait leads northeastward (from Istanbul) to the Black Sea. The sea was called the Propontis by the ancient Greeks, and was later named after its main island.