Cite this page as: Beth Harris, "Tassili’s rock walls were commonly sponged with water in order to enhance the reproduction of its images, either in trace, sketch, or photograph. This washing of the rock face has had a devastating effect on the art, upsetting the physical, chemical, and biological balance of the images and their rock supports. Many of the region’s subsequent visitors—tourists, collectors, photographers, and the next generation of researchers—all captivated by Lhote’s “discovery”—have continued the practice of moistening the paintings in order to reveal them. Today scholars report paintings that are severely faded while some have simply disappeared. In addition, others have suffered from irreversible damage caused by outright vandalism: art looted or stolen as souvenirs. In order to protect this valuable center of African rock art heritage, Tassili N’Ajjer was declared a National Park in 1972. It was classified as a World Heritage Site by UNESCO in 1982 and a Biosphere Reserve in 1986.," in Smarthistory, April 30, 2016, accessed May 23, 2018, https://smarthistory.org/running-horned-woman-tassili-najjer-algeria/750092958_15cf326cf0_b/.