In November 1987, aerial reconnaissance over pastureland at Carn in County Galway picked out an irregularly shaped field that would have been almost impossible to read from the ground. What the photographs revealed was an enclosure roughly 300 metres east to west and about 70 metres north to south, tracing a long, shallow rectangle across a gentle south-facing slope. On the ground, the boundary that defined it had collapsed almost entirely into the soil, a low, barely perceptible bank of earth and stone that in places had all but disappeared.

The enclosure sits in what is now ordinary working farmland, and modern field boundaries have since been cut straight across it, parcelling up its interior without apparent regard for what lies beneath. Natural hollows are scattered across the ground within, and a house occupies the south-eastern corner of the old field's extent. The age and precise purpose of the original boundary are not recorded, but enclosures of this kind in the west of Ireland can represent anything from early medieval farming arrangements to much older land divisions, their banks slumping gradually over centuries until only a change in light or a low winter sun reveals that something once ran across a hillside in a particular direction. This one would almost certainly have remained unrecorded without that November flight in 1987.