hi, I visited newgrange a Neolithic site in Ireland a few years ago..it dates back to 5 thousand years...it is built to allow the solstice sun to penetrate into the cave at daybreak...what I found most interesting was the names scratched on the interior walls of young lovers of the 18th centuries, it was first discovered by a farmer in the 1800s, he was digging out rocks to build walls, he thought it was a hill, he discovered it was a man made cavern, actually built by stoneage peoples, he left it partially opened with a grass mound on top.....the kids in the 18th century found it handy as a place to do what young lovers do everywere,... and they always seem to leave their names to posterity...