Moscow is the capital city and the most populous federal subject of Russia. The city is a major political, economic, cultural and scientific center in Russia and in Eastern Europe. According to Forbes 2013, Moscow has the largest number of billionaire residents in the world, has been ranked as the ninth most expensive city in the world by Mercer and is one of the world's largest urban economies, being ranked as an alpha global city according to the globalization and World Cities Research Network and is also one of the fastest growing tourist destinations in the world. Moscow is the northernmost and coldest megacity and metropolis on earth, the second most populous city in Europe after Istanbul and the 8th largest city proper in the world, as well as the largest amongst high income economies.
Istanbul 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 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.