The history of exploration by citizens or subjects of the Russian Federation, the Soviet Union, the Russian Empire, the Tsardom of Russia and other Russian predecessor states forms a significant part of the history of Russia as well as the history of the world. At , Russia is the largest country in the world, covering more than a ninth of the Earth’s land mass. In the times of the Soviet Union and the Russian Empire the country's share in the world's land mass reached 1/6. Most of these territories were first discovered by Russian explorers (if indigenous peoples of inhabited territories are not counted). Contiguous exploration in Eurasia and the building of overseas colonies in Russian America were some of the primary factors in Russian territorial expansion.