California is one of the richest repositories of Native American rock art in North America. Rock art is an inclusive term for symbols created on natural rock surfaces: pictographs are painted rock art, petroglyphs are rock art chipped or pecked into stone, and geoglyphs are large-scale figures made by clearing the natural stone called desert pavement. Rock art reflects ancient religious beliefs imposed on the natural landscape and is a fragile and endangered part of the cultural heritage of all Californias. The Great Mural Art of Baja California is a world-renowned collection of rock art showing human figures and many animal species and illustrating the relationship between humans and their environment; the paintings reveal a highly sophisticated culture. Their composition and size, as well as the precision of the outlines and the variety of colors, make this an impressive testimony to a unique artistic tradition.