This is just a few hundred yards up the road from Dyffryn House and is well worth the visit. It dates back to about 4000BC which means that when you stand in front of it you are really looking at history. Consider that for a while, it was built 6000 years ago by a people whose lives were very different from ours! Isn't that humbling!
There is of course a legend attached, a very familiar legend - it is that anyone who spends a night at this site on the evenings preceding May Day, St John's Day (23rd June), or Midwinter Day would either die, go raving mad, or become a poet. Now where have I heard that before?