Greece was linked to the outside world through the use of ships. Greece is a long peninsula, so ships were necessary for travel.
The seas and islands.
The seas and islands provided great ports and henceforth outside contact.The Dardenelles
The Mediterranean.
The Silk Road
They were both stories about gods and Greece
There was no Olympic Games outside of Greece before the first one was recorded.
greek language and culture
You just answered your own question. Most Greeks did not go to other countries. In fact most of them were scared of the outside world. Most stayed in their home island of Greece.
there life's written on the outside
Outside of academia I do not think linked list are important, a btree is important. As for a real-world application, I do not recall one. I did use a linked list back in the days of the Apple 2/Commodore 64 but That was before hard drives (were affordable) and before I got my hands on btree source code.
During ancient times, Athenians thought of non-Hellenes, i.e.) people outside of Greece, as barbarians.
greek language and culture
Peloponnese peninsula