Saint Petersburg is the second largest city in Russia and the country's cultural heart. It has a population of over 5 million people and was formerly known as Petrograd and Leningrad. The city has many major attractions, including 221 museums, 2000 libraries, over 80 theaters, and 100 concert organizations. Some of its most famous cultural attractions are the Hermitage Museum, Kazansky Cathedral, Church on Spilled Blood, and St. Isaac's Cathedral.