Istanbul is a city located in the Marmara Region of Turkey and one of the 81 provinces of the Republic of Turkey. It is the country's largest and most populated province in terms of population. It is one of the leading cities economically, historically, and socio-culturally. The city of Istanbul ranks 34th in the world in terms of economic size. According to the ranking made by considering the municipal boundaries in the list of cities according to population, it ranks first in Europe and sixth