Russia, or the Russian Federation, is a country spanning Eastern Europe and Northern Asia. It is the largest country in the world, covering over 17 million square kilometres, and encompassing more than one-eighth of Earth's inhabited land area. Russia extends across eleven time zones, and has borders with sixteen sovereign nations. It has a population of 146.2 million; and is the most populous country in Europe, and the ninth-most populous country in the world. Moscow, the capital, is the largest city in Europe, while Saint Petersburg is the nation's second-largest city and cultural centre. Russians are the largest Slavic and European nation; they speak Russian, the most spoken Slavic language, and the most spoken native language in Europe.
The East Slavs emerged as a recognisable group in Europe between the 3rd and 8th centuries AD. The medieval state of Rus' arose in the 9th century. In 988, it adopted Orthodox Christianity from the Byzantine Empire, beginning the synthesis of Byzantine and Slavic cultures that defined Russian culture for the next millennium. Rus' ultimately disintegrated until it was finally reunified by the Grand Duchy of Moscow in the 15th century.