Carnac Alignments, France
The Carnac alignments are an exceptionally dense collection of megalithic sites around the village of Carnac, in Brittany, consisting of alignments, dolmens, tumuli and single menhirs. More than 3,000 prehistoric standing stones were hewn from local rock and erected by the pre/proto-Celtic people of Brittany, and are the largest such collection in the world. Most of the stones are within the Breton village of Carnac, but some to the east are within La Trinité-sur-Mer. The stones were erected at some stage during the Neolithic period, probably around 3300 BC, but some may date to as old as 4500 BC.
Although the stones date from 4500 BC, modern myths were formed which resulted from 1st century AD Roman and later Christian occupations, such as Saint Cornelius, a Christian myth associated with the stones held that they were pagan soldiers in pursuit of Pope Cornelius when he turned them to stone. Brittany has its own local versions of the Arthurian cycle. Local tradition claims that the reason they stand in such perfectly straight lines is that they are a Roman legion turned to stone by Merlin.
This was somewhere we had heard about and researched before we left the UK. I am so glad we visited as the pictures you see online do not do the place justice. This is an incredible site with row upon row of stones as far as the eye can see. Not only that but there are a huge amount of dolmens and other neolithic sites in the area. See the around Carnac page. This is an area you could easily spend a week or two exploring all the sites.