[0xffff2]

North and South America are on different tectonic plates, while Europe and most of Asia are on a single plate. If anything, the geological definition of continents seems to support separate Americas and a unified Eurasia.

[TylerE]

The best argument for separating the Americas is probably the existence of the Darien Gap. I’m not sure there is more inhospitable route in a populated area anywhere in the world.

[panxyh]

I stand corrected then. Always assumed that the Ural lied on border of two plates.

[Beldin]

And to acknowledge India as a separate continent.