In 2019, a curious square shape measuring approximately 25 metres on each side appeared on geophysical surveys of the subsoil carried out at the La Peyrouse site in the Dordogne region of France. Archaeologist Eneko Hiriart, a researcher at the CNRS, led the investigation. Very quickly, the first archaeological excavations carried out on the site confirmed his intuition: this mysterious square corresponded to the ghostly imprint of the enclosure ditch of a Gallic sanctuary, the first ever discovered in Aquitaine. While mistletoe gathering, magic potions and human sacrifices on dolmens in the middle of impenetrable forests still haunt the popular imagination, archaeological research is now enabling us to move beyond the clichés. As discoveries are made, the religion of the Gauls is gradually being revealed.