Arthur’s Quoit came as something of a surprise.The huge neolithic tomb rises from the plateau behind St David’s Head, the angle and ridge on the capstone seeming to shadow the lines of Carn Llidi beyond. The capstone is around twenty feet long and  over eight feet wide, supported by a single orthostat that holds the point of the stone around five feet from the ground. At first glance, you assume that somewhere during its five thousand year history, the other two orthostats that would have supported it must have fallen and the earthen mound that covered it been eroded away. There are many such places where this has happened.

A closer look, though, makes you question that assumption. It is true that there are stones strewn broken on the ground that could have been supporting stones… but the whole thing looks right, just as it is in this place. The…