The geomorphosites are important objects concerning the geoheritage inventories, for they stimulate the interest of local stakeholders about projects of territorial valorisation. However, a great number of geomorphosites are not clearly identified due to what should be named a mask of "avisibilité", a term different from invisibility. The authors have coined the neologism "non-visibility" (avisibilité) to be defined and explain in the present paper, a full set of four masks interposed between the object and the observing person. First, there is of course the natural invisibility as in the case of the underground cavities. Second, another form of invisibility is due to the limits of perception itself, because a site or parts of it may be hidden. Third, the scientific and additional values of a geomorphosite are often covered by a layer of picturesque discourse which dissembles the real and fundamental interest of the site. Fourth, invisibility may happen due to land use planning (e.g. dam lake). Very often, the values of the site fully disappear under the various superimposed masks. Concerning geoheritage, it then becomes necessary to develop a process of revelation in order to make all the values of a geomorphosite accessible and understandable.