Some observations on Stone circles...
I lived in Cork, Southern Ireland for a few years and while there, bought the local maps of the area. There are more standing stones and stone circles there than in any other place in Europe! I highlighted them all on the maps and my wife and I went visiting them. She is acutely clairvoyant and sees subtle reality at will.
Every single standing stone on its own and every stone in a circle complex had / has a yellow coloured SUBTLE energy channel that enters it from above, vertically. We sometimes found an odd stone in a field and she'd see instantly whether it was 'real' or not - no channel - no 'bona fide' standing stone. We once found a place where some landowner had actually 'moved' a stone circle because the stones were present but they were 5m away from the energy channels that were entering the ground where they had once stood; the land owner had seen fit to move the structure to build a road into the field. Other times we found stones that had fallen from their original placing because the channel was always vertical but the stone sometimes was lying down - giving the first impression that its channel was entering it at one end only - but not the case, it's just that the stone had toppled over.
By contrast, we also visited the 'Druids circle' in Margam, near Swansea; it has no channels at all - having been erected by the local druids in the late 70's.
Another interesting thing was that many stone circles have not only the vertical channels, but a horizontal one that connects each stone in a ring fashion, again, always yellow in colour. Avebury, Stonehenge and Callanish all have the ring formation.
When I would walk through the ring channel, entering the circle, it would appear to 'bend away' from me to a point where it would then flip and reconnect behind me at my back to the outside of the circle. I would also slowly move my arm over the top of a stone so she could watch what happened to the energy channel; the same thing occurred. By these clear experiments we concluded that this energy channel does not ordinarily make contact with Man. Makes me wonder about all the folks that visit stone circles to 'feel the energies'
So, there is 'something' to these particular stones and sites that sets them apart from just ordinary groups of stones... Perhaps, long ago, Man had the ability to see these channels and was simply marking the places where they enter the earth - or the channels formed as a result of some ancient special rituals carried out by those people so long ago; who knows!