Souterrain, Dooish, Co. Donegal

These subterranean passages, found across Ireland but particularly common in Ulster, were typically constructed between the 6th and 12th centuries. Souterrains consist of stone-lined tunnels and chambers dug into the earth, often associated with ringforts or other settlement sites, and whilst their exact purpose remains debated amongst archaeologists, they likely served as storage spaces for food, temporary refuges during raids, or both.