Mass tourism to historic sites, ancient monuments, historic buildings and to archaeological sites (such as cave paintings) rapidly results in their degradation.
The pharaohs tombs in Egypt, for example, are visited daily by an average of 5,000 visitors. It has been estimated that they leave behind an estimated 50 pints of perspiration, which mixed with bacteria and dust provides the perfect climate for molds and chemical reactions damaging to the wall-paintings. These are visibly flaking away from the reliefs. Elegantly decorated walls that were intact 10 years ago have now crumbled to dust. In other situations, such processes are aggravated by flash photography.