At Killowen in County Kerry, however, that modest hollow, sitting just east of the centre of a rath, may be the only visible sign of something altogether more interesting lying beneath the surface.

A rath is a ringfort, the most common type of early medieval enclosure in Ireland, typically a raised circular area bounded by one or more earthen banks and ditches and used as a farmstead from roughly the fifth to the twelfth centuries. Within and around such enclosures, archaeologists frequently encounter souterrains, which are artificially constructed underground passages or chambers, usually built from stone and earth, that served a variety of purposes including storage, refuge, and possibly ventilation for perishable goods. The depression recorded at Killowen, just off-centre within its associated rath, has the character of a collapse or subsidence consistent with an underground void, and is tentatively interpreted as evidence that a souterrain may lie below. No excavation appears to have confirmed this, and the feature remains, for now, a suggestion rather than a certainty.

What makes this site quietly compelling is precisely that ambiguity. The ground hints at something, and the hint is all there is.