What was the issues of the Lascaux Caves (Paleolithic)?

The issue has been the preservation of over 2,000 works of
paleolithic art. The cave itself was discovered by teenagers in 1940 and thereafter was
opened as a public exhibit; however the roughly 1200 visitors per day created an immense
accumulation of carbon dioxide which damaged the figures and led to the closing of the
cave. Aside from carbon dioxide, an air conditioning system was added to the caves which
changed the degree of humidity present which together with light emitted by the lighting
system encouraged the growth of black mold. This led to closing of the caves and
attempts to remove the mold; unfortunately new forms of mold have appeared and the
process of removing it is tedious and time consuming. There is no guarantee that the
fungi can be safely and completely removed.