Looking west from the tower

The Colorado is invisible in the canyon below because it enters the inner canyon here. The reason there is a Grand Canyon is the Kaibab Plateau popped up and the Colorado has cut down through it. See http://www.durangobill.com/Paleorivers_preface.html for a big (really big!) discussion of the geology.

There's a wide, flat valley to the east and north, through which the Little Colorado River has cut a 1,000' deep canyon to get down to the level of the Colorado.

The Colorado itself comes from Utah through Marble Canyon. The land around Marble Canyon is also flat, but to the north are the Vermillion Cliffs, creating a great red wall. On the other side of Marble Canyon are the Echo Cliffs. The end of Marble Canyon is the junction with the Little Colorado coming in from the east. So, the whole complex goes like this: The Colorado comes out of Glen Canyon into Marble Canyon, where it goes for maybe 40 miles or so across the flat plain until it reaches the Kaibab, meets the Little Colorado and starts into the Grand Canyon proper.

This bottom picture is looking east from the Tower. You can see the flat plain and in the middle distance the great crack in the earth where the Little Colorado runs.