The "Well of Souls" is a pair of geological formations resulting from a process of dissolution of karst and gypsum, by the action of subterranean waters. These formed caverns, the "roofs" of which then collapsed. The diameter of the largest of the two sinkholes is 200m, the height over 80m and depth over 21m. The bottle-green water irremediably draws the eye in a sand-coloured mountain landscape. A spectacle that won't fail to make an impression.