Making Prehistory

摘要

Not so many years ago, if you wanted to see prehistoric cave art in its original setting, you could. You might visit Altamira in Spain or Lascaux in France, where, standing in the caves of our Paleolithic ancestors, you could view the stylized and vibrant bison, horses, and other beasts they painted there some 15,000 years ago. Sadly this close-up experience is now available to few people, because by visiting the cave paintings, humans had begun to destroy them. The carbon dioxide that visitors exhaled was making the atmosphere inside the caves more acidic, dissolving the surfaces of the limestone walls and loosening the paintings. At the same time, all those tourists―as many as 1000 a day at Altamira in the 1970s―were raising temperatures inside the caves to the point where bacteria began growing on the artwork.