Russia, the largest country in the world, occupies one-tenth of all the land on Earth. It spans 11 time zones across two continents (Europe and Asia) and has coasts on three oceans (the Atlantic, Pacific, and Arctic). The Russian landscape varies from desert to frozen coastline, tall mountains to giant marshes. Much of Russia is made up of rolling, treeless plains called steppes. Siberia, which occupies three-quarters of Russia, is dominated by sprawling pine forests called taigas. Russia has about 100,000 rivers, including some of the longest and most powerful in the world. It also has many lakes, including Europe's two largest: Ladoga and Onega. Lake Baikal in Siberia contains more water than any other lake on Earth.