Istanbul (Turkish: İstanbul) is Turkey's most populous city as well as its cultural and financial hub. Located on both sides of the Bosphorus, the narrow strait between the Black Sea and the Marmara Sea, Istanbul bridges Asia and Europe, both physically and culturally. Istanbul's population is estimated to be between 12 and 19 million people, making it also one of the largest cities in Europe and the world.
Sultanahmet-Old City - Essentially the Constantinople of the Roman, Eastern Roman/Byzantine, and much of the Ottoman periods, this is where most of the famous historical sights of Istanbul are located.
Galata - Housing many of the nightlife venues of the city, this district includes Beyoğlu, Istiklal Street, and Taksim Square also its own share of sights and accommodation.
New City - Main business district of the city with many modern shopping malls and districts such as Elmadağ, Nişantaşı, and Etiler.
Bosphorus - European bank of the Bosphorus dotted by numerous palaces, parks, water-front mansions, and bohemian neighbourhoods, such as Beşiktaş and Ortaköy.
Golden Horn - Banks of Golden Horn, the estuary that separates the European side into distinctive districts. Eyüp, with an Ottoman ambience, is located here.