Istanbul, historically known as Byzantium and Constantinople, is the largest city of Turkey. Istanbul metropolitan province (municipality) had 14.4 million people living in it, which is 18% of Turkey’s population and the 2nd largest metropolitan area in Europe (including the Asian side of the city) after London and Moscow. The city in its administrative limits had 8.8 million residents counted in the latest Turkish census from 2000. Istanbul is a megacity, as well as the cultural, economic, and financial centre of Turkey. It is located on the Bosphorus Strait and encompasses the natural harbour known as the Golden Horn, in the northwest of the country. It extends both on the European (Thrace) and on the Asian (Anatolia) sides of the Bosphorus, and is thereby the only metropolis in the world that is situated on two continents. Istanbul is a designated alpha world city.
During its long history, Istanbul 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). When the Republic of Turkey was proclaimed on 29 October 1923, Ankara, which had previously served as the headquarters of the Turkish national movement during the Turkish War of Independence, was chosen as the new Turkish State’s capital. Together with Essen (Germany) and Pécs (Hungary), Istanbul was chosen as a joint European Capital of Culture for 2010 and the European Capital of Sports for 2012. Istanbul is currently bidding to host the 2020 Summer Olympics. The historic areas of the city were added to the UNESCO World Heritage List in 1985. The city covers 39 districts of the Istanbul province.
Istanbul is primarily known for its Byzantine and Ottoman architecture, but its buildings reflect the various peoples and empires that have ruled its predecessors. Genoese, Roman, and even Greek forms of architecture remain visible in Istanbul alongside their Ottoman counterparts. Similarly, while the Hagia Sophia and imperial mosques dominate much of the city’s skyline, the city is also home to a number of historic churches and synagogues.
More than two thousand years following the departure of the Greeks, few examples of Istanbul’s Greek architecture have survived. Perhaps the most prominent relic of the Greek era is Maiden’s (Leander’s) Tower. Residing on an islet in the Bosphorus just off the coast of Üsküdar, Maiden’s Tower was first built by the Greeks in 411 BC to guide ships within the strait. Since then, however, the tower has undergone a number of enlargements and restorations, rendering its connection to the Greeks tenuous, and today merely serves as an observation point.