Preserving the Naica Cave of Crystals

To see or not to see? That, for delicate historical and artistic artifacts, is the question. Paintings, tapestries and other works of art must often be displayed in dim lighting within protective casing to avoid degradation of the pigments and other materials. For art conservators, the painful truth is that the best way to preserve priceless and irreplaceable objects would be to not display them at all.

At the Lascaux cave in southwest France, with its famous and astonishing 17,000-year old wall art, keeping things off display has been more or less the solution since the 1960s. Light, air and the breath of sightseers had previously led to the appearance of lichens, moulds and crystal precipitation on the cave walls, and the authorities decided that access to the original caves had to be highly restricted. Visitors today are directed to a painstaking replica of the cave.