Russia is located in both Europe and Asia. The Ural Mountains are considered the separation boundary for the two continents. The Asian side of Russia is physically bordered to the south by Kazakhstan, Mongolia, and China, with an extremely short border shared with the tip of North Korea. The Pacific Ocean is to the east with the Bering Strait separating Russia from North America. The boundaries of European Russia include its southern border in the Caucasus Mountains with Georgia and Azerbaijan. This portion of Russia protrudes south of 50 degrees latitude. The Caucasus Mountains are the tallest mountain chain in Russia and Europe. The Black Sea and the Caspian Sea create natural boundaries on either side of the Caucasus Mountains. The main borders with Eastern Europe include the large countries of Ukraine and Belarus. European Russia occupies almost 40% of the total area of Europe, and most of its people reside in Europe.