Scientists and managers of the World Heritage Site of Altamira Cave in the Cantabria region of Spain are deeply concerned that recent calls to reopen the cave, closed to mass tourism since 1977, would lead to the cave paintings' destruction.
     Recent studies have shown that intense human traffic caused the deterioration of the paintings, produced by modern humans living in or near the cave between 18,500 and 14,000 years ago.
     The cave was first discovered in 1897 by amateur archaeologist Marcelino Sanz de Sautuola, who interpreted the paintings as belonging to the late Palaeolithic era - claims considered controversial until several other similar sites were discovered in 1902.  The artwork - which includes images of bison, dear, wild boar, horses, goats, abstract shapes and handprints - was created from pigments made from ochre, hematite and charcoal, and is considered among the most complex Palaeolithic art ever found. In 2008, scientists using Uranium-thorium dating techniques determined that some of the artwork may be between 25,000 and 35,000 years old.

Edited from NewScientist, Popular Archaeology (6 October 2011)