Istanbul | History, Population, Map, & Facts - Britannica

City site

The old city contains about 9 square miles (23 square km), but the present municipal boundaries stretch a great deal beyond. The original peninsular city has seven hills, requisite for Constantine’s “New Rome.” Six are crests of a long ridge above the Golden Horn; the other is a solitary eminence in the southwest corner. Around their slopes are ranged many of the mosques and other historic landmarks that were collectively designated a UNESCO World Heritage site in 1985.

By long tradition, the waters washing the peninsula are called “the three seas”: they are the Golden Horn, the Bosporus, and the Sea of Marmara. The Golden Horn is a deep drowned valley about 4.5 miles (7 km) long. Early inhabitants saw it as being shaped like a deer horn, but modern Turks call it the Haliç (“Canal”). The Bosporus (İstanbul Boğazı) is the channel connecting the Black Sea (Karadeniz) to the Mediterranean (Akdeniz) by way of the Sea of Marmara (Marmara Denizi) and the straits of the Dardanelles. The narrow Golden Horn separates old Istanbul (Stamboul) to the south from the “new” city of Beyoğlu to the north; the broader Bosporus divides European Istanbul from the city’s districts on the Asian shore—Üsküdar (ancient Chrysopolis) and Kadıköy (ancient Chalcedon).

Britannica Quiz Guess the City by Its River Quiz

Like the forces of history, the forces of nature impinge upon Istanbul. The great rivers of Russia and middle Europe—the Danube, Don, Dnieper, and Dniester—make the Black Sea colder and less briny than the Mediterranean. The Black Sea waters thrust southward through the Bosporus, but beneath them the salty warm waters of the Mediterranean push northward as a powerful undercurrent running through the same channel.