This one, in the reclaimed wet pasture of Knocklong West in County Limerick, offers nothing so obliging. There is no visible trace of it at ground level, no ridge in the grass, no depression in the field. What exists here is, in a sense, a site defined entirely by its absence, known only because a camera mounted on an aircraft happened to pass overhead on the 3rd of November 1984.

The possible barrow, a burial mound of the kind built during the Bronze Age, was identified not by excavation or fieldwork but through the examination of aerial photographs taken on behalf of Bórd Gáis Éireann during a gas pipeline survey. The images, captured at a scale of 1:10,000, showed what analysts interpreted as a potential site lying roughly 60 metres from the townland boundary with Doonmoon, and approximately 95 metres south of two confirmed ring-barrows, circular earthwork enclosures associated with prehistoric funerary ritual, which are recorded separately in the national monuments register. The site was never marked on Ordnance Survey Ireland historic maps, and when researchers returned to the question using Digital Globe orthophotos taken between 2011 and 2013, and again with Google Earth imagery, no surface remains were visible. The record was compiled by Fiona Rooney and uploaded to the national database in June 2021, where it sits with the cautious designation of "possible site."

There is, practically speaking, nothing to see here, and that is rather the point. The surrounding landscape is ordinary improved farmland, and without access to the original aerial photographs or the monument record, a visitor standing in this field would have no reason to suspect anything lay beneath. The confirmed ring-barrows 95 metres to the north are themselves unassuming features of the kind that can be easy to miss without prior knowledge of what to look for. The value of this particular record lies less in what can be visited and more in what it illustrates about how prehistory is recovered in Ireland, piece by piece, through the patient reading of light, shadow, and crop variation caught in a single aerial pass over four decades ago.