Located on the top of the mound, to the left of the Crêperie, the Musee du Tertre opens its doors to you during the months of July and August to present to you through its exhibition "Voyage dans le Temps" objects dating from the prehistoric site discovered in Mont -Dol (- 110,000 years ago when Neandertal man hunted mammoths) as well as a collection of rocks and flint. Panels illustrate the history and geology of Mont-Dol. Maps, a polarizing microscope and a film complete the information. A commented discovery walk around the mound is also offered every afternoon at 3 p.m. by student guides in geology or paleontology (except Mondays).