A house turned into a prison, camouflaged among similar dwellings, for several centuries it bore witness to dramatic detention conditions, as well as safeguarding precious documents. The Spanish prison in Seui, a medieval village on the border between southern Sardinia and Olgiastra, is a 2-storey square building set amongst narrow village streets and can be reached only via an evocative underpass, known as su Porci, lined with stone houses with carved wooden doors and wrought-iron balconies.

In the mid-17th century, the building became a penal facility of the Incontrada of Barbagia di Seulo, which belonged to the Duchy of Mandas. It was eventually turned over to the Savoy judicial system and then to the Italian government, until it was finally closed in 1975. It stands entirely surrounded by other buildings and prisoners had no view of the outdoors.