This is not the romantic underground of myth but something far more practical and far stranger for its ordinariness: a souterrain, an early medieval underground structure built from dry stone, typically used for cold storage or as a refuge, turning up in what is now a quiet residential area beside the grounds of Clanricarde House in Ballintemple.

The structure was discovered and investigated in 1909, and a scholarly analysis published by McCarthy in 1977 gives us the clearest picture of what was found. The chamber itself measured roughly 2.4 metres in length, 1.5 metres wide, and 1.5 metres high, accessed through a narrow entrance shaft only about 60 centimetres across in both width and height. The walls were corbelled, meaning the stones were laid in overlapping courses that gradually closed in toward the top, allowing flat capstones to be set across the gap without the need for mortar or arch work. It is a technique that appears again and again in Irish souterrains, deceptively simple and remarkably durable. What made this particular example more intriguing was the physical evidence recovered during investigation: stones showing signs of burning, and a small quantity of bones identified, tentatively, as possibly belonging to a horse. Whether these point to a specific event, a ritual deposit, or something more incidental is not resolved, and the ambiguity is part of what lingers.