Moscow (Moskva) (Russian: Москва́, romanised: Moskva, IPA: [mʌsk'va] see also other names) is the capital of Russia and the country's economic, financial, educational, and transportation centre. It is located on the Moskva River in the Central Federal District, in the European part of Russia. The name of the city is usually pronounced [ˈmɒskəʊ] in British English, and either [ˈmɑskaʊ] or [ˈmɑskoʊ] in American English. Moscow (Moskva) is the most populous city in Europe, whose population constitutes about 7% of the total Russian population. Historically, it was the capital of the former Soviet Union and the Grand Duchy of Moscow, the pre-Imperial Russian state. It is the site of the Kremlin, which now serves as the ceremonial residence of the President of Russia. Moscow also remains a major economic centre and is home to a large number of Russian billionaires; it was recently named as the most expensive city in the world for expatriate employees.It is home to many scientific and educational institutions, as well as numerous sport facilities. It possesses a complex transport system that includes the world's busiest metro system, which is famous for its