Mausoleum of Glanum
France
The Mausoleum of Glanum is a Gallo-Roman monument erected by either 40 BC during the late Roman Republic, or between 30 and 20 BC during the transition from Republic to Empire, located south of Saint-Rémy-de-Provence, France. It stands outside the pomerium of the city of Glanum, which is now an archaeological site. It is in an exceptional state of conservation, one of the best preserved Roman structures in the world.
Data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).