In the Dublin area, we took a day to go out and visit Brú na Bóinne,
an area with two extensive Neolithic sites studded with burial mounds,
standing stones, henges, and passage tombs. Newgrange is the more famous
of the two, but I think Knowth is more interesting and better
OK, even tombs have to be mowed once in a while..
The main passage tomb (actually two of them, back to back, but not connecting) is surrounded by carved stones; since they're abstract, it's unlikely we will ever know what the makers intended. The entrances with the tomb are aligned with the rising sun at the two equinoxes.
The entrance to the one passage tomb that's open is marked by dark and light stones laid out in a pattern:
Other tombs on the site have less dramatic entrances. There is a standing stone circle and a commanding view of the Boyne River valley from the top of the main tomb.