That curve is, in all likelihood, all that physically remains of a ringfort, one of the thousands of roughly circular earthen enclosures built across Ireland during the early medieval period, typically used as defended farmsteads. The interior of whatever once stood here is now a vegetable garden, which gives the site a pleasing kind of continuity, agricultural land serving agricultural purposes across perhaps a thousand years or more.

Local tradition held that there was both a fort and a cave at this spot, the cave almost certainly referring to a souterrain, an underground stone-lined passage that ringfort builders frequently attached to their enclosures for storage or refuge. Whether any trace of that passage survives beneath the soil is not recorded. The earthworks themselves have vanished entirely, absorbed back into the landscape, leaving only that anomalous kink in the road as a kind of fossil outline. It is the sort of thing that is very easy to drive past without a second thought, though once you know what you are looking at, the geometry of that bend becomes harder to ignore.