Petroglyph National Monument protects one of the largest petroglyph sites in North America, where American Indians and Spanish settlers carved designs and symbols onto basalt boulders 400 to 700 years ago along Albuquerque's West Mesa. Established in 1990, the monument preserves the petroglyphs and related archeological sites and is cooperatively managed by the City of Albuquerque Open Space Division and the National Park Service. Surveys have confirmed more than 24,000 petroglyphs along the volcanic escarpment. These images are a valuable record of cultural expression and hold profound spiritual significance for certain contemporary American Indian tribes and for heirs of local Spanish land grants. Although many images resemble those found on kiva murals and painted pottery, the original meaning of each petroglyph is known only to its creator. Even when their interpretations or purposes are not understood in the 21st century, the petroglyphs preserve the beliefs and virtues of their makers and remain a vital part of the heritage of American Indian people living in the region as well as part of the nation's heritage. Common images include macaw parrots associated with Pueblo culture, trade, and communication of ideas with MesoAmerican cultures; spirals associated with wind, water, spiritual emergence, and an individual's journey through life; geometric and abstract forms, circles, and squares linked to nomadic desert cultures that likely created the monument's oldest petroglyphs 2000 to 3000 years ago; and handprints used to mark territory and sacred places and left as the emblem of medicine men. Animal images throughout the Southwest could represent Pueblo family clan affiliations or communicate a food resource, and macaw petroglyphs attest to extensive trade networks among native peoples of North, Central, and South America.