Over the span of 20 years, 2.3 million granite blocks, with an average weight of 2.5 tons, would have to be cut, quarried from hundreds of miles away, and absolutely perfectly placed at a rate of 1 block every 4 and a half minutes.
How was this really achieved?
Even adding decades to the timeline, how did they do it?
Either the time frame must be longer, or it was Aliens, or they had some weird ancient technology that allowed them to be very quick and efficient