Thanks for sharing, alexg.
About you question, we have seen monolithic architecture pretty everywhere:
-Perperikon,
-Mycenae
-Peru
-Japan
-Stonehenge
-Egupt
-Mesoamerica
-China
-Uzbekistan
-Mesopatamia
-Australia
-Bosnia
...
Concerning the origins?
I don't know
PS: Wait, i will use my time technology and let you know soon... (Jesting the kid i am inside)
Did you read the Wikipedia article? It's Roman / Byzantine architecture built on top of an old Thracian settlement. It's "megalithic" in the sense
that large blocks of stone were used to build it, but who built it, how, and why (it's a temple that got converted to Christianity) are not
mysterious. We know less about Knossos than we do about Perperikon - and the Cretans used bigger rocks to build their palace, if that's what gets you
going
No, Europeans did not "invent" megalithic structure. It developed independantly in many parts of the world. if it all had a common origin,
megalithic structures would have more in common than just being structures made from big blocks o' rock.