Last week I was up at Brú na Boinne, near Drogheda, visiting Knowth and Newgrange prehistoric passage graves. They are magnificent neolithic sites, older than both the Great Pyramid at Giza and Stonehenge. At the entrance to Newgrange the tour guide pointed this megalith out as probably the most photographed stone in the world. He was probably right. The carving is quite beautiful and mysterious. There is one other tri-spiral carved on a stone at the end of the interior passage (no photos allowed inside).
As with the megalithic kerbstones at Knowth, I was completely fascinated by the Neolithic art from more than 5000 years ago.
There is no final agreement between archaeologists about whether the designs are scientific, religious or linguistic. It's anyone's guess as to what was going through the minds of the prehistoric makers.
Around the passage grave at Newgrange there is also a stone circle. The tour guide didn't say anything about it this time, nor do I fully remember from previous tours of the site, but I think the circle came later, so time-wise is comparable to Stonehenge and Avebury, which I have had the pleasure of visiting many years ago.
Some years ago the tour guide had implied that the placement of the sea-rolled grey stones and the white quartz that form the facade of Newgrange were entirely made up. This time the guide gave a plausible reason for the pattern, which would be quite startling to prehistoric viewers; the archaeologist Professor MJ O'Kelly had done numerous experiments on the patterns formed by fallen rocks before meticulously deciding each stone's placement on the facade.
Since I had been to the nearby site of Knowth earlier in the day and seen the jumble of sea rolled grey stones and white quartz (neither of which are local stone) surrounding the largest monument there, I could imagine O'Kelly's reconstruction rationale. Although the tour guide at Knowth suggested that the stones may be to form a path rather than a facade, I couldn't imagine walking on these lumps!