1. Istanbul, Turkey
Istanbul (/ˌɪstænˈbuːl/; Turkish: İstanbul) is the largest city in Turkey, constituting the country's economic, cultural, and historical heart. With a population of 14.1 million, the city forms the largest urban agglomeration in Europe, second largest in the Middle East and the fifth-largest city in the world by population within city limits. 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—one of the world's busiest waterways—in northwestern Turkey, between the Sea of Marmara and the Black Sea. Its commercial and historical centre lies in Europe, while a third of its population lives in Asia.2. Rome, Italy
Rome (/ˈroʊm/; Italian: Roma pronounced [ˈroːma] Latin: Rōma) is a city and special comune (named "Roma Capitale") in Italy. Rome is the capital of Italy and also of the Province of Rome and of the region of Lazio. With 2.9 million residents in 1,285.3 km2 (496.3 sq mi), it is also the country's largest and most populated comune and fourth-most populous city in the European Union by population within city limits. The urban area of Rome extends beyond the administrative city limits with a population of around 3.8 million. Between 3.2 and 4.2 million people live in Rome metropolitan area. The city is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of Tiber river. Vatican City is an independent country within the city boundaries of Rome, the only existing example of a country within a city: for this reason Rome has been often defined as capital of two states.