The oldest human artifacts found in Grand Canyon are nearly 12,000 years old and date to the Paleo-Indian period. There has been continuous use and occupation of the region since that time. The park has recorded more than 4,800 archaeological resources with an intensive survey of nearly 3 percent of the park area. Today Grand Canyon National Park receives close to 5 million visitors each year—a far cry from the annual visitation of 44,173 that the park received in 1919. The Grand Canyon of the Colorado River is a world-renowned showplace of geology. The Grand Canyon’s magnificent display of layered rock reveals the region’s geologic history like no other place. Other geologic forces you can see and study at Grand Canyon include movement of the Earth’s tectonic plates, erosion by wind and water, and volcanic activity. Grand Canyon is located on the Colorado Plateau. The plateau’s arid climate and the carving power of wind and water have produced many striking erosional forms, culminating in the Grand Canyon.  Originally deposited as sediments and lava flows, these rocks were intensely metamorphosed about 1,750 million years ago. Magma rose into the rocks, cooling and crystallizing into granite, and welding the region to the North American continent. https://www.grandcanyon.org/learn/canyon-facts/grand-canyon-geology