Istanbul Istanbul Istanbul (, or or ; ), historically known as Byzantium and before 1924 as Constantinople, is the most populous city in Turkey and the country's economic, cultural, and historic center. Istanbul is a transcontinental city in Eurasia, straddling the Bosporus strait (which separates Europe and Asia) between the Sea of Marmara and the Black Sea. Its commercial and historical center lies on the European side and about a third of its population lives on the Asian side. The city is the administrative center of the Istanbul Metropolitan Municipality (coterminous with Istanbul Province), both hosting a population of around 15
Architecture of Istanbul Architecture of Istanbul The Architecture of Istanbul describes a large mixture of structures which reflect the many influences that have made an indelible mark in all districts of the city. The ancient part of the city (the historic peninsula) is still partially surrounded by the Walls of Constantinople, erected in 5th century by the Emperor Theodosius II to protect the city from invasion. The architecture inside the city proper contains buildings, statues, and functional constructions which came from Byzantine, Genoese, Ottoman, and modern Turkish sources. The city has many architecturally significant entities. Throughout its long history, Istanbul has acquired a