The territory of Siberia extends eastwards from the Ural Mountains to the watershed between the Pacific and Arctic drainage basins.
The Russian Army was directed to establish forts farther and farther east to protect new settlers from European Russia.
Siberia stretches southwards from the Arctic Ocean to the hills of north-central Kazakhstan and to the national borders of Mongolia and China.
With an area of 13.1 million square kilometres (5,100,000 sq mi), Siberia accounts for 77% of Russia's land area, but it is home to just 40 million people—27% of the country's population.
Most scientists believe this resulted from the air burst of a meteor or a comet.
Even though no crater has ever been found, the landscape in the (uninhabited) area still bears the scars of this event.