Bryce Canyon, on the Colorado Plateau. The odd thing about the Colorado plateau: it is perfectly flat until one walks up to the edge of a Canyon carved out of soft sandstone by a river.
Bryce Canyon is created by the Paria river which has carved out the scenic hoodoos of the Canyon, exposing the sedimentary sandstone at 8000 ft elevation.
Parts of the Colorado plateau are at 10,000 ft. elevation. Very hard to tell until you get your car stuck in the mud and you have to get out and push!