Appearance
Eurasia is a landmass that consists of two continents:
The distinction between the two is to some extent arbitrary. Regions such as the Caucasus can be counted as part of either and some countries such as Russia and Turkey are partly in both.
Of course the two have always been linked; see Silk Road for the historic trade routes or Trans-Siberian railway for probably the most famous overland trip between the two continents today.