İstanbul, historically known as Byzantium and Constantinople, is the largest city in Turkey. Approximately 18% of the Turkey's population resides in İstanbul. İstanbul. Located on the Bosphorus Strait and encompassing the natural harbour known as the Golden Horn, İstanbul is the cultural, economic, and financial center of Turkey.
During its long history, İstanbul has served as the capital of the Roman Empire (330-395), the Eastern Roman (Byzantine) Empire (395-1204 and 1261-1453), the Latin Empire (1204-1261), and the Ottoman Empire (1453-1922).
İstanbul is located on both the European (Thrace) and on the Asian (Anatolia) sides of the Bosphorus, making it the only metropolis in the world that is situated on two continents.