Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west and the Mediterranean Sea to the south. It comprises the westernmost part of Eurasia.
Since around 1850, Europe is most commonly considered to be separated from Asia by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas and the waterways of the Turkish Straits. Though the term "continent" implies physical geography, the land border is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects East-West cultural, linguistic and ethnic differences, some of which vary on a spectrum rather than with a sharp dividing line. The border does not follow political boundaries, with Turkey, Russia and Kazakhstan being transcontinental countries.