History of the Grand Canyon area stretched along a 278-mile (447 km) segment of the Colorado River from the southern border of Glen Canyon National Recreation Area to the eastern boundary of Lake Mead National Recreation Area. Grand Canyon National Park was designated a World Heritage Site on October 24, 1979. In 1935, Hoover Dam started to impound Lake Mead south of the canyon. Conservationists lost a battle to save upstream Glen Canyon from becoming a reservoir. The Glen Canyon Dam was completed in 1966 to control flooding and to provide water and hydroelectric power. Seasonal variations of high flow and flooding in the spring and
Indigenous peoples of the North American Southwest the border of Texas and Mexico. Several Spanish explorers described this culture which was related to or derivative from the Jornada Mogollon. Between 700 and 1550 CE, the Patayan culture inhabited parts of modern-day Arizona, California and Baja California, including areas near the Colorado River Valley, nearby uplands, and north to the vicinity of the Grand Canyon. The Fremont culture inhabited sites in what is now Utah and parts of Nevada, Idaho and Colorado from 700 to 1300 CE. Archaeologists use cultural labels such as Mogollon, Ancestral Pueblo peoples, Patayan, or Hohokam to denote cultural traditions within the prehistoric American