Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the largest country in the world by area, extending across eleven time zones and sharing land borders with fourteen countries. It is the world's ninth-most populous country and Europe's most populous country. Russia is a highly urbanised country including 16 population centres with over a million inhabitants. Its capital and largest city is Moscow. Saint Petersburg is Russia's second-largest city and its cultural capital.
The East Slavs emerged as a recognised group in Europe between the 3rd and 8th centuries CE. The first East Slavic state, Kievan Rus', arose in the 9th century, and in 988, it adopted Orthodox Christianity from the Byzantine Empire. Kievan Rus' ultimately disintegrated; the Grand Duchy of Moscow led the unification of Russian lands, leading to the proclamation of the Tsardom of Russia in 1547. By the early 18th century, Russia had vastly expanded through conquest, annexation, and the efforts of Russian explorers, developing into the Russian Empire, which remains the third-largest empire in history. However, with the Russian Revolution in 1917, Russia's monarchic rule was abolished and eventually replaced by the Russian SFSR—the world's first constitutionally socialist state.