They appear as low, horseshoe-shaped mounds, typically dark with charred and shattered stone, and for a long time nobody was entirely sure what they were for. The leading explanation today is that they were outdoor cooking sites, used during the Bronze Age by heating stones in a fire, dropping them into a water-filled trough until the water boiled, and then cooking meat in the resulting heat. Other theories have proposed brewing, hide-working, or bathing. The site recorded at Darragh in County Clare is one such monument, sitting quietly in the rural landscape of a county that holds a remarkable concentration of prehistoric remains.

Clare's geology and topography, boggy ground in particular, have helped preserve many of these features where they might otherwise have been ploughed away or built over. Fulachtaí fia are most commonly found near water sources, which makes practical sense given that the whole process depends on a ready supply. The burnt, fragmented stone that gives the mounds their characteristic dark colour is called fire-cracked rock, a byproduct of repeatedly heating stones that are then plunged into cold water, causing them to fracture. Over centuries of use and abandonment, this debris accumulates into the low crescent shape that survives in fields and bogs across Ireland today. The Darragh example joins a long catalogue of such sites throughout the county, each one a small, largely silent record of organised outdoor activity from somewhere in the second millennium BC.