Geological feature found in Arizona?
The Grand Canyon of the Colorado River is an adequate feature particulary when viewed from the top of the north rim the south rim and the canyon bottom. To have seen the canyon without those perspectives means that you have not seen the canyon. A relatively new excurtion is via helicopter which while relatively expensive provides an explosive visual panorama. A ride through the rapids isn't cheap but remains an essential part of the ex[erience. Less popular but still memorable is the joruney down via burro which may be an essential part of the Grand Canyon experience