From the ground, a field outside Kilkea in County Kildare looks unremarkable, the kind of quiet agricultural landscape that occupies much of the county's interior. But seen from the air, two near-perfect circles emerge from the soil, revealed not by any upstanding structure but by the subtle discolouration of crops growing differently over buried features beneath. These ghostly rings, each estimated at around twenty metres in diameter, belong to a category of monument that is almost entirely invisible to anyone standing among them.

The circles are defined by what archaeologists call cropmarks, the faint but legible traces left when buried ditches, or fosses, cause vegetation above them to grow taller or ripen at a different rate than the surrounding field. The pattern here suggests the presence of ring-ditches or ringbarrows, both terms for a class of prehistoric funerary or ritual enclosure in which a circular ditch, sometimes accompanied by an internal or external bank, delineates a central area that may once have held a burial mound, a cremation deposit, or some form of ceremonial space. The two examples at Kilkea sit close together, which is not unusual; such monuments often appear in loose groupings, suggesting that a place once considered significant continued to attract successive acts of burial or commemoration across generations. The evidence for them comes from a single aerial photograph, taken under the reference CUCAP AVM 1, in conditions where the cropmark contrast was sufficient to make the circular fosses legible from above.