Two examples of conservation of two rock art sites take into consideration the spatial independence between the prehistoric work and the natural milieu sheltering it. The first study concerns the case of the Lascaux cave, located in the temperate zone; the second study has to do with rock shelters located in the desertic zone and is an approach to the conservation of neolithic paintings in the Tassili n'Ajjer mountains. A glossary of 220 words reflecting the multidisciplinary character of terms associated with the safeguard of rock art is the basic vocabulary in use along the scientific and technical path toward the preservation of the works.