This one announces itself with nothing at all. Beneath a field in Rooves More, County Cork, a souterrain, an underground stone-lined passage or chamber typically associated with early medieval settlement, has collapsed and been filled in, leaving no visible surface trace. There is simply ground where ground has always appeared to be.

The souterrain is thought to have lain at the centre of a possible ringfort, the circular enclosure, usually defined by an earthen bank and ditch, that served as a farmstead across much of early medieval Ireland. What happened to this one is relayed only through local memory: at some point the underground structure gave way, the hollow was infilled, and the site was effectively absorbed back into the landscape. There is no surviving record of when the collapse occurred, what the souterrain contained, or how extensive it may have been before it went. The ringfort itself is classed as possible rather than confirmed, which gives the whole site a quality of layered uncertainty, a structure beneath a structure, both of them now largely conjectural.