I've now finally watched Hancock's documentary. It's a 'slick' production for sure, and many of the sites presented are places I've never heard of. As others have stated, there is a lot of guess-work included that is not dirctly supported by evidence. All in all, I was left with a wish that the documentary would've gone depper into the details and technical analysis of these megaliths. Despite all the experts and fancy gadgets, the evidence and 'data' was, in my opinion, almost hurried through and then the bulk of the time was invested in going through the myths and legends. Well, that's one way of going at it but I myself prefer a more 'technical' and detailed approach.
As an answer to my wish above, I came upon this crowdfunded documentary in which also Hancock features. I'd say this one is much, much more interesting and does, indeed, go into the very details of things. There are, though, a number of conclusions and suggestions that at least to me sound like 'wishful thinking' and guess-work...especially regarding the playing around with numbers, measurements, and golden ratios etc. Maybe you guys with a more robust mathematical know-how can say if these guys are seeing something that isn't really there?
In any case, the most impressive and astounding thing in this documentary are the caves in India that are presented. I mean, wow! Be sure to watch the segement at ca 2 hours when they revisit the caves and produce 3D models of them. Really mind boggling! And the theory of why many ancient megalithic walls were built assymetrically sounds plausible: it was to miminize the impact of earth quakes and other natural disasters...to make them more durable. Oh, and the measurements showing how amazingly smooth those surfaces are, makes the whole construction appear almost supernatural...how on Earth did they build those?!
Despite the a bit 'tin-foilish' argumentation at times,
I highly recommend watching this one. For being a crowd funded production it's amazingly well made: