Somewhere beneath a field in Broadfield, County Kildare, lies a circular monument that has never been excavated, never been mapped on the ground, and never, as far as anyone can tell, been visited with the intention of finding it. What gives it away is a ring of slightly different-coloured crop, roughly thirteen metres across, that appeared in aerial photographs taken in the summer of 2018. This kind of ghostly outline, known as a cropmark, forms when buried features such as ditches or walls affect how the soil retains moisture, causing the plants above them to grow at a slightly different rate. In dry weather especially, the difference becomes visible from above, and the hidden geometry of an ancient landscape briefly announces itself.

The feature at Broadfield is consistent with a ring-ditch barrow, a burial monument type found widely across Ireland and Britain, typically dating to the Bronze Age or earlier. The ditch would originally have encircled a central mound or grave, and while the above-ground earthwork has long since been ploughed flat or eroded away, the cut of the ditch into the subsoil preserves enough of a mark to be legible from the air. At approximately thirteen metres in diameter, this is a modest example of the type, though size tells us little about the importance or date of whoever may have been interred there. The cropmark was identified from Google Earth imagery captured on 28 June 2018, a detail that matters: that particular summer was unusually dry across much of Ireland and Britain, and the drought conditions of 2018 revealed an extraordinary number of previously unrecorded sites across the country as parched fields gave up their secrets.