Moscow is located on the Moskva River in western Russia and has a population of about 10.5 million. Moscow is one of the most important cities and tourist destinations due to the natural and cultural areas that it offers to tourists, gardens, parks, wonderful markets, attractive streets, museums, and architectural monuments. It is a highly integrated city. Among its most important tourist attractions: the historic Kremlin Castle built since the twelfth century, the Moscow Zoo, which is the largest zoo located in all of Russia and not only in Moscow, and the Red Square, which is the central square in the city and where thousands of residents and tourists gather daily. Moscow also includes many natural parks and gardens, such as Kolomenskoye Park, Neskushny Park on the right bank of the Moscow River, and Luzhny National Park, which is a nature reserve.