The problems of restoring the Acropolis are no longer the same as in the 19th century. Today the dangers are internal and external: foundations attacked by humidity, wear of the stone by the passage of tourists, cleavage of the stone caused by rust on the iron clamps. The most serious threat remains the disintegration caused by the action of the atmosphere, and this appears difficult to resolve. Various chemical products are being tested on samples of ancient marble, but no protective substance has yet been discovered. -- AATA