Europe is a landmass variously recognized as part of Eurasia or a continent in its own right, located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It comprises the westernmost peninsulas of the continental landmass of Eurasia, it shares the continental landmass of Afro-Eurasia with both Asia and Africa and is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east. Europe is commonly considered to be separated from Asia by the watershed of the Ural Mountains, the Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea, and the waterways of the Turkish Straits. Although much of this border is over land, Europe is recognized as its own content in some parts of the world because of its great physical size and the weight of its history and traditions.