Somewhere beneath a south-east-facing slope at Knockaderry in County Waterford, there is a burnt mound that nobody can currently find. It was recorded in the 1950s, noted in a National Museum of Ireland file, and then, in practical terms, lost. Not destroyed, not excavated, simply absorbed back into the pasture above it, invisible at ground level and without a confirmed precise location.

Burnt mounds are among the more enigmatic features of the Irish prehistoric landscape. They are typically low, kidney-shaped spreads of fire-cracked stone and charcoal-rich soil, found near water sources, and they tend to date to the Bronze Age, roughly 2000 to 500 BC. The leading theory is that they represent cooking sites, where stones were heated in fire and dropped into water-filled troughs to bring liquid to the boil, though some archaeologists have proposed uses ranging from hide-working to bathing. The Knockaderry example fits the general pattern in at least one respect: the bottom of a slope is exactly the kind of damp, low-lying ground where these sites cluster. What set it apart briefly from the thousands of other recorded examples was simply that someone noticed it in the mid-twentieth century, wrote it down, and then the ground closed over it again.