It's interesting how diverse some of these films are on Silbury Hill. In the first film shown the commentator says that the hill took some 4 million man hours to complete, yet in the Channel Four doco 'The Heart of the Hill' it says 18 million! That's a huge difference isn't it.
And another aspect I find interesting is the suggestion that the hill was always gleaming white with many people suggesting that's what it was designed to be so that it stood out. Is there any real evidence to support this? Even the final stage of construction would have taken so long that wouldn't the chalk have greened up as work continued...unless it was purposely kept clean during construction that is and after completion? The same has been said of Abvebury's Great Circle's bank, but again, that would green up as work continued surely. The only chalk you see today on the bank is where people walk along it, but I noticed a year or two back when sections were closed off for maintainance growth returned within weeks.