Istanbul, Turkey Istanbul is the most populous city in Turkey and the country's economic, cultural, and historic center. Istanbul's strategic position on the historic Silk Road, rail networks to Europe and the Middle East, and the only sea route between the Black Sea and the Mediterranean have produced a cosmopolitan populace. Istanbul is located in north-western Turkey within the Marmara Region. Istanbul has a borderline Mediterranean climate. Istanbul has numerous shopping centers, from the historic to the modern. The Grand Bazaar, in operation since 1461, is among the world's oldest and largest covered markets. Istanbul is also famous for its seafood restaurants.