These photos are from the exhibition Pierres secrètes: Mythologie préceltique en Forêt de Fontainebleau (Secret stones: Prehistoric mythology in the forest of Fontainebleau) at Musée de Préhistoire Île-de-France in Nemours. The exhibition featured petroglyphs, or rock carvings, done on portable stones found hidden in the Forest of Fontainebleau. It seems like the rock art was…