Pronounced boscawen-oon, this is a large and well-defined stone circle (actually an ellipse), consisting of 19 upright stones, plus one leaning stone near the centre. It was erected sometime during the Bronze Age: the name derives from three Cornish words, bos (farmstead), scawen (elder tree) and un (pasture).
It's an important cultural site, which is probably why the Gorseth Kernow (the bardic organisation founded to revive Cornwall's language and culture) chose to hold its inauguration ceremony here in 1928.
There are no road signs to the circle, but having an OS map makes it relatively easy to find. From Penzance, take the A30 west towards Land's End, passing through the village of Drift. Follow the road and pass the turning to Boscawenoon Farm. Soon after, you'll see a grassy layby on the left-hand side of the road with a wooden walkers' gate and a small stone marker – a trail leads from here to the stone circle.