There is a particular category of Irish archaeological site that exists almost entirely as an absence. At Toghereen in County Kildare, a fulacht fia once lay in level pasture, and by the middle of the twentieth century it had already been reduced to a cartographic footnote. The Ordnance Survey's 1939 six-inch map records it with the phrase "Site of", a designation that signals the thing is gone rather than merely obscured.

A fulacht fia is a type of Bronze Age cooking site, typically identified by a horseshoe-shaped mound of heat-shattered stone and charcoal built up beside a trough or pit. The trough would have been filled with water, heated by dropping fire-cracked stones into it, and used to boil meat or perhaps serve other purposes that archaeologists still debate. These sites are common across Ireland, particularly in low-lying, waterlogged ground, which makes the flat pasture at Toghereen a plausible enough setting. What makes this particular example notable is not what it was, but how thoroughly it ceased to be. By 1986, a field inspection found no visible surface trace whatsoever. The mound, the scorched stones, the hollow in the ground, all of it had gone into the landscape without leaving so much as a slight rise in the grass.