St. Hallvard's Cathedral
Oslo Municipality, Norway
St. Hallvard's Cathedral (Hallvardskatedralen) was the former Oslo Cathedral. It fell into disrepair in the 17th century and is today in ruins. The site is located between Bispegata and St. Halvards gate in Oslo, Norway.
Cathedral data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).