Europe is the world’s second-smallest continent by surface area, covering about 10,180,000 square kilometres (3,930,000 sq mi) or 2% of the 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 (although the country has territory in both Europe and Asia), while Vatican City is the smallest. Europe is the third-most populous continent after Asia and Africa, with a population of 739–743 million or about 11% of the world’s population. Europe has a climate heavily affected by warm Atlantic currents, tempering winters and enabling warm summers on most of the continent, even on latitudes that have severe climates in North America and Asia. Further from the Atlantic, seasonal differences increase, but the mildness of the climate remains.