Grand Canyon

The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, one of the first national parks in the United States. It has a viewing platform shaped like a U.

The Lost Hero
In The Lost Hero, the Grand Canyon is visited by Jason, Piper and Leo on a Wilderness School field trip. Jason is discovering his amnesia while they are here. On the sky-walk a Ventus (Dylan) attacks Jason, Leo, Piper and Gleeson Hedge. Leo fell down from the Grand Canyon and so did Piper. Jason jumps over the skywalk to save Piper and used his power to control the air currents around them to save both of them.

Jason comes up with the "crazy" idea that some crazy god stuck his knife into the ground and dragged it across to form the canyon. It is very likely that this is exactly how the canyon was formed.