Met a lot of masons in my lifetime. They were all human. Never met an extraterrestrial alien. Hard to imagine why they would bother to work monumental stone. It's also hard to understand why people have the delusion that only "ancient aliens" could work stone. Find me an alien first before spewing such nonsense.
Gotcha!
On the other hand, what about the proposition that these feats of engineering and expert stone dressing couldn’t have been done by humans all those thousands of years ago—so the builders must have been aided by Ancient Aliens.
And it was probably built as a temple to worship those Ancient Aliens.
Huh? Huh? What about that?