Temple of the Moulin du Fâ
The temple of the Moulin du Fâ is an ancient fanum, a Celto-Roman temple located in the commune of Barzan in the Charente-Maritime department of France. Possibly dedicated to Mars, it is part of the relatively uncommon group of circular-plan temples in Roman Gaul.
Source: Wikipedia — Temple of the Moulin du Fâ (CC BY-SA 4.0)