Eurasia

Eurasia is the combined landmass of Europe and Asia in the northern part of Earth. It has the Atlantic Ocean on its west, and the Pacific Ocean to the east. The Arctic Ocean is to its north, and the Mediterranean and Indian Ocean to its south. It is the largest of the continents. Its name comes from adding the "Eur" from "Europe" to "Asia". It and Africa form a part of the world called "Afro-Eurasia".

Some geographers say Eurasia is one continent, because Europe and Asia are mostly on the same tectonic plate and do not have a sea between them. The Ancient Greeks divided the world they knew into Europe, Asia and Africa. To them, the Aegean Sea was the division between the Balkan Peninsula in Europe and Asia Minor in Asia. North of the Sea of Marmara, the Greeks thought the lands on the western side of the Black Sea was Europe and the eastern side was Asia. The ancient Greeks did not know very much about the lands north of the Black Sea. Since Classical Antiquity, people have talked about Asia and Europe separately, so it is now a tradition to see them as two continents.

Some other continents, which are not completely divided by sea, are joined together by a thin strip of land (called an isthmus). An example is North America and South America, which are connected by the Isthmus of Panama. Europe and Asia are not divided by a sea, nor by any isthmus.

Outside of geological definitions, Eurasia also includes the Indian subcontinent and the Arabian Peninsula.

Sometimes Eurasia is divided into West Eurasia and East Eurasia. Here, the dividing line is the Ural Mountains. West Eurasia includes Europe and the Middle East. Historians sometimes add North Africa to West Eurasia, because the Sahara Desert divides North Africa from Sub-Saharan Africa, and it is as difficult to cross as a sea. Also, North Africa is culturally linked to Europe by the Mediterranean Sea.