In a field near Beaconstown in County Kildare, there is nothing to see at ground level. No mound, no stone, no depression in the earth. The only evidence that something of significance lies beneath the surface came from the air, when a circular mark emerged in the growing crop above, tracing the outline of a structure that has otherwise vanished entirely from the landscape.

The feature is a ring-ditch, the buried remnant of a circular ditch that once enclosed a space of ritual or funerary significance, most commonly associated with prehistoric burial practice. Over centuries, the ditch fills with soil and the land is ploughed flat, leaving no visible trace. But in dry summers, when crops draw moisture unevenly from the ground, the deeper disturbed soil of a filled ditch retains slightly more water, and the plants above it grow a little taller and greener than their neighbours. From altitude, these differential growth patterns, known as cropmarks, resolve into shapes that correspond to long-buried features. An aerial photograph, referenced as GB96.FZ.21, recorded precisely this at Beaconstown, showing a ring-ditch complete with what appears to be an entrance gap oriented towards the north-east.