These prehistoric sites are both fragile and vulnerable. Excavation and study have radically altered their storage conditions. This calls for heightened care and the implementation of protection measures so that they can be handed down to future generations. These open-air sites are now closed for preservation reasons, which thus profoundly changes their original appearance. For those that are still open to the public, their fragility means that the number of visitors must be limited, and that awareness-raising actions are required via heritage activities and mediation involving researchers.