Canyon de Chelly -
White Sands -
Needles district -
here is a link to the Canyonlands N.P trailguide
Saguaro Park, Sonoran Desert -
Bryce Canyon -
Natural Bridges national monument -
The three bridges in the park are named Kachina, Owachomo, and Sipapu (the largest), which are all Hopi names. A natural bridge is formed through erosion by water flowing in the stream bed of the canyon. During periods of flash floods, particularly, the stream undercuts the walls of rock that separate the meanders (or "goosenecks") of the stream, until the rock wall within the meander is undercut and the meander is cut off; the new stream bed then flows underneath the bridge.