Istanbul

Istanbul (/ˌɪstænˈbuːl/; Turkish: İstanbul) is the largest city in Turkey, constituting the country's economic, cultural, and historical heart. Its commercial and historical centre lies in the European part of Eurasia, while about a third of its population lives in the Asian part. With a population of 14.1 million, the city forms the largest urban agglomeration in Europe as well as the largest in the Middle East, and the sixth-largest city proper in the world. Istanbul's vast area of 5,343 square kilometers (2,063 sq mi) is coterminous with Istanbul Province, of which the city is the administrative capital. Istanbul is a transcontinental city, straddling the Bosphorus strait in northwestern Turkey between the Sea of Marmara and the Black Sea.

Founded on the Sarayburnu promontory around 660 BC as Byzantium, the city now known as Istanbul developed to become one of the most significant cities in history. For nearly sixteen centuries following its reestablishment as Constantinople in 330 AD, it served as the capital of four empires: the Roman Empire (330–395), the Byzantine Empire (395–1204 and 1261–1453), the Latin Empire (1204–1261), and the Ottoman Empire (1453–1922). It was instrumental in the advancement of Christianity during Roman and Byzantine times, before the Ottomans conquered the city in 1453 and transformed it into an Islamic stronghold and the seat of the last caliphate.