Russia is the largest country in the world, spanning northern Eurasia from eastern Europe to the Pacific Ocean. It has a wide variety of landscapes, from Arctic deserts in the far north to forest and steppe zones further south. Russia was founded as a centralized state in the 15th century under Grand Duke Ivan III and later strengthened by Tsars Ivan the Terrible and Peter the Great. In the 19th century, Tsar Alexander II expanded Russia's territory significantly while also abolishing serfdom, though with heavy restrictions remaining on freed peasants.