That moment came on 28 June 2018, when satellite imagery captured a cropmark tracing the outline of an ancient enclosure, a ghostly ring pressed into the growing crop above it.

Cropmarks form when buried features, such as the filled-in ditches of old enclosures, affect how plants grow above them. Soil that once filled a ditch tends to retain more moisture, producing lusher, taller crops in dry conditions, while the outline of buried walls can stunt growth. From the air or a satellite image, these differences resolve into shapes that reveal what lies beneath. The Ballylarkin enclosure, circular and approximately 26 metres in diameter, fits broadly within the tradition of ringforts and enclosed settlements that were common across Ireland from the early medieval period onward, though its precise date and function remain unconfirmed. The site was identified and reported by Simon Dowling and Jean-Charles Caillère, whose scrutiny of publicly available Google Earth imagery brought it to attention.