I have loved this series TP - upvoted and resteemed. Here is my take though.

Just as artists and craftsmen exist today, they existed thousands of years ago too - and they set about to create beauty that our engineers, steemians etc create now.

And they had time on their hands, vast numbers of of perhaps underemployed peoples and they would have mastered their surrounds - say stone, rocks, mining, carving & sculpting. Stone-masonry in general.

Now take this a step further - they, like us build something and they want it to be perfect. So they cut, grind, sand to the get a 'great' fit and a smooth finish.

Now add a couple of thousand years of stone on stone weight, wind and water and all of a sudden that 'great' fit becomes a 'too perfect fit' one that was not possible by ancient technology.

In the end it was merely great craftsmanship combined with gravity and nature.

I know this isn't as romantic as what some historians would have you believe - but often the most logical explanation is the right one.

IMO.

SirKnight.