The geography of Russia describes the geographic features of Russia, a country extending over much of northern Eurasia. Comprising much of eastern Europe and northern Asia, it is the world's largest country in total area. Due to its size, Russia displays both monotony and diversity. As with its topography, its climates, vegetation, and soils span vast distances. From north to south the East European Plain is clad sequentially in tundra, coniferous forest (taiga), mixed and broadleaf forests, grassland (steppe), and semi-desert (fringing the Caspian Sea) as the changes in vegetation reflect the changes in climate. Siberia supports a similar sequence but is predominantly taiga. The country contains 40 UNESCO Biosphere reserves.