After the famous Fontaine de Vaucluse immortalized by Petrarch, the most significant river supplied by Mont Ventoux is the Toulourenc, a small river who’s source is at the foot of the Aulan Castle, close to Montbrun-les-Bains. It is 30 kilometers long, winding through deep and wild valleys, descending down to Ouvèze having flowed through many a picturesque site, clearly limiting the northern slope of the Mont Ventoux. This slope is marked out by villages such as : Reilhanette, Savoillans, Brantes, St-Léger-du-Ventoux.