Greece is world famous, especially for its beaches, its friendly people, its good food and the ancient ruins that date back to when the ancient Greeks invented democracy a few thousand years ago. Of course there are other things to experience in the country on the south-eastern edge of Europe - you can hike, climb mountains or take cheap ferries from island to island.
Or you are interested in old ruins like me, not that kind of old the ancient greeks are. In this case you will find some interesting places with "mordern" abandoned ruins - hotels, houses, cars and bunkers.
Map https://pinmapple.com/?post=travelling-greece-modern-ruins-in-the-oldest-land (thank you, @pinmapple, and @for91days too!