This baffling monument is the only one of its kind in Cornwall, consisting of two upright menhirs flanking a hollow, ring-shaped stone. Squeezing through the stone was said to be a cure for infertility and rickets, but quite what the original purpose of the stone was is still a complete mystery. Its name derives from the Cornish for 'stone of the hole'.
The site is situated along a side track 5 miles south of Morvah – look out for the turning sign to Chûn Castle, and park in the next layby. The track leads from here.