The wildest thing about Tulum (for me) was standing on that big stone slab where guys used to get their beating hearts cut out. Crazy looking at the same scenery/sky as a lot of people did right before they became part of the hereafter. Kinda' surreal.
I bet we could have construction tolerances similar to those witnessed in ancient Egypt if they (1) made the architect second only to the Pharoah (they got that one correct) and (2) used whatever labor necessary at whatever cost necessary rather than constantly using the low bidder!
(I imagine having it wrong being punishable by death is a pretty good incentive to get it correct too...)