what is the name of the river that runs through istanbul
), once known as Constantinople and Byzantium before that, is the most populous city in Turkey, and the country's economic, cultural, and historical center. Istanbul is a transcontinental city in Eurasia, straddling the Bosphorus strait between the Sea of Marmara and the Black Sea.stanbul is one of the world's most populous cities and ranks as world's 5th-largest city proper and the largest European city. Founded on the Sarayburnu promontory around 660 BCE as Byzantium, the city now known as Istanbul developed to become one of the most significant cities in history.