Why is Europe often considered seprate from asia?

The boundary between Europe and Asia is bizarre among mainland boundaries since of its to a great extent mountain-and-river-based characteristics north and east of the Black Ocean.

Europe is considered a separate continent from Asia because of its distinct historical, cultural and political identity, rather than any clear geographical demarcation.

A large part of Turkey lies in Asia, however, culturally and politically, it has been closer to Europe and therefore sees itself as a European country.