I do find the Megaliths intriguing. Last night on the National Geographic channel they had a special on it. My comment in regards to this article is that I think it is misleading in that you could read it and think this was a single culture that lasted up to 10,000 years. In reality, prior to 5500 BC, any monuments had to be associated with Mesolithic peoples, around 5000-3000 BC could have been Neolithic cultures like the Maritime Impressed Wares, and then at the peak when the Stonehenge huges stones came in, it was probably the Bell Beaker Cultures and the famous "Amesbury Archer." This was not one, singular culture that lasted 5,000 years.
... civilization whose apex occurred as much as 12,000 years before...
The people belonging to this megalithic culture displayed highly advanced technologies at an almost incredibly early date. For example, by 4000 BC, the Neolithic inhabitants of the Orkneys, Hebrides and Shetlands were demonstrably using skin boats and voyaging nearly out of sight of land......
Barry Cunliffe has pointed out the relative homogeneity of the Megalithic Culture – he says in the late bronze age “had a warrior from the Algarve sailed to Aberdeenshire he would have found much in local behaviour and equipment that was very familiar.”