At Lisheennashingane in County Kerry, a rath, which is a circular earthen ringfort of the kind built throughout early medieval Ireland, contains a quiet puzzle: the 1846 Ordnance Survey six-inch map marks a feature labelled simply as a cave in the south-eastern quadrant of the enclosure, yet on the ground today there is nothing to see.

The cave in question was almost certainly a souterrain, an underground stone-lined passage or chamber typically built in association with raths during the early medieval period, roughly between the sixth and twelfth centuries. Souterrains were used for storage, and possibly for refuge, dug beneath or beside domestic enclosures. Their entrances and roofing stones could collapse over centuries, leaving no surface trace, or the feature could have been deliberately backfilled at some point after the map was made. The fact that the Ordnance Survey surveyors noted it in 1846 suggests something was visible or locally known at that time, making the subsequent disappearance itself a small historical episode.