I have visited Crucuny a number of times over the years. It is an impressive mound and I used to like catching out of the corner of my eye from the road to Carnac.
It is pot-luck as to whether you find it covered in six foot high vegetation or shaved clean by the council’s rather aggressive looking lawnmower.
I will, at some point, work out how many of these Grand Tumuli were intervisible in a landscape with less trees...