This one in Ballynacree, County Tipperary, gives nothing away at all. Standing on the north-facing pasture slope where it sits, a visitor would have no reason to suspect that anything lay beneath their feet. The enclosure is, by every ordinary measure, invisible.

What makes its existence known at all is a single aerial photograph, reference Bruff No. 5/2030, in which a circular area roughly twenty metres in diameter resolves itself from the surrounding land. Cropmarks and soil shadows of this kind appear when buried features, perhaps the filled-in ditch of an early medieval enclosure, affect the growth of grass or crops above them in ways that only become legible from altitude. The site never appeared on any edition of the Ordnance Survey six-inch map series, meaning it escaped the attention of the cartographers who, across the nineteenth and twentieth centuries, recorded so much of Ireland's surviving monument landscape. Its existence was noted and compiled by Jean Farrelly, whose work brought it into the formal record in 2011.

There is no meaningful visitor experience to describe here, and that is part of what makes the site genuinely interesting as a category of place. It belongs to a class of monument that exists, at present, almost entirely as information, a shape seen once from the air, measured approximately, and then absorbed into the documentary record while the field above it continues to be grazed as it always was.