Ruins of St. Justinian's Chapel, Porthstinian

St Justinian's Chapel in Pembrokeshire, Wales, is now a roofless shell; the current structure was probably erected in the 16th century on earlier foundations, which may date from the time of the 6th and 7th century Saint Justinian to whom it is dedicated. The chapel is a Grade I listed building.

Data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).