I can’t recount the history as I suffer from shock and awe when visiting these things: but they are great nevertheless
What I do want to say is: while the manufacture and construction was an epic activity the number of observations recorded, calculations done and trials and errors made to get the setting out correct is staggering and no records exist!
I can’t imagine they picked this site at random and got lucky when they did the setting out.
Today in construction, putting aside the cost and contractural impact, things change while on site as we have flexibility of planning, but moving many tons of rock a few inches to the left or raise it by foot could not happen.