system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are Europe and Asia considered two continents?
gpt
The ancient Greeks first developed the idea of a continent.  They saw that the Mediterranean divided Europe from Africa, the Red Sea divided African from Asia, and with their limited knowledge of geography, assumed the Black Sea divided Asia from Europe.

They were wrong, but the notion stuck, and has been reinforced by a culture divide that runs roughly along the same lines.