Eurasia

Eurasia is the combined landmass of Europe and Asia in the northern part of the 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 Pacific Ocean to its south. It is the largest of the continents. It includes the Indian subcontinent. If one adds Africa, it becomes "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. Knowing little of the land north of the Black Sea, they took that and the Sea of Marmara as dividing Europe from Asia. Since then, people have talked about Asia and Europe as two regions so it is now a tradition.

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

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. Europe and Asia are not divided by a sea, nor by any isthmus.