This one at Annaghaskin, in County Dublin, does none of that. Standing in the improved pasture on its gentle south-facing slopes, you would see nothing unusual at all, just grass and the distant outline of the Sugarloaf Mountains on the horizon. The enclosure exists, in practical terms, only as a ghost in a photograph.

What we know about the site comes almost entirely from a single aerial photograph taken in 1971, referenced in the archaeological record as FSI 3.658/7. From that image, researchers could read cropmark evidence, the subtle variations in vegetation colour and growth that betray buried features beneath the soil, for a subcircular enclosure roughly 40 metres in diameter. Cropmarks form when buried ditches or banks affect how moisture reaches plant roots, causing crops or grass above them to grow differently from the surrounding field, often only visible from altitude and in the right season. The 1971 photograph also captured a levelled field boundary extending about 45 metres from the northern portion of the enclosure. On the ground, none of this survives as visible earthwork; agricultural improvement of the pasture has long since smoothed everything flat. The record was compiled by archaeologists Geraldine Stout and Padraig Clancy, with a revised upload dated April 2018.

Because the enclosure leaves no surface trace, there is little to observe during an ordinary visit. The site sits on private farmland, and access would require the landowner's permission. For anyone with a serious interest, the most rewarding approach is to consult the original aerial photograph through the relevant national archive, where the cropmark evidence remains readable. The south-facing aspect of the slope means conditions for cropmark visibility are best in a dry summer, when soil moisture stress is greatest, which is worth bearing in mind if aerial or drone photography is your aim. The Sugarloaf provides a reliable landmark for orienting yourself in the landscape, even when the enclosure itself gives you nothing to find.