Europe comprises the westernmost part of Eurasia which is generally considered as separate from Asia by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the Bosphorus strait. Yet the borders of Europe are in fact arbitrary, as the primarily physiographic term "continent" also incorporates cultural and political elements.
Europe is the world's second-smallest continent by surface area, covering about 10.1 million square kilometres or just 2% of Earth's surface and about 6.8% of its land area. Of Europe's approximately 50 countries, Russia is by far the largest by both area and population, taking up 40% of the continent, while the Vatican City is the smallest. Europe is the third-most populous continent after Asia and Africa, with a population of 740 million - 11% of the world's population. Europe is, relatively, traveller friendly with intrepid adventures found all over especially in the east of the continent.