Most canyons were formed by a process of long-time erosion from a plateau or table-land level. The cliffs form because harder rock strata that are resistant to erosion and weathering remain exposed on the valley walls. Rainwater, runs into the extensive basin above the slot canyon sections, picking up speed and sand as it rushes into the narrow passageways. Over time the passageways eroded away, making the corridors deeper and smoothing hard edges in such a way as to form characteristic 'flowing' shapes in the rock.The Pueblo people considered the Grand Canyon ("Ongtupqa" in the Hopi language) a holy site.
