A shallow depression, roughly seven metres long and four metres wide, marks where the roof of a stone-lined souterrain gave way around 1916, leaving the land slightly sunken and the underground passage it once covered largely out of reach.

A souterrain is an underground stone-built gallery or chamber, typically associated with early medieval ringforts in Ireland, and thought to have served variously as storage space, a place of refuge, or both. The ringfort at Moyge is the parent site here, an enclosed settlement of the kind that dots the Irish countryside in its thousands, though each carries its own particular history of occupation and use. What makes this example quietly notable is the specificity of its collapse, dated by local tradition to around 1916, a moment when the underground structure finally succumbed to whatever combination of ground pressure and time had been working at it. The depression that remains, oriented north to south and less than a metre deep, is essentially the earth's surface having adjusted to the void beneath it.