The Great Canyon was a natural canyon on the planet of Teyr.
During the Clone Wars, the Confederacy of Independent Systems set up a base near the Great Canyon, inside a landed Lucrehulk-class battleship.
General K'Kruhk led his clone troopers into battle with the Separatists through the Great Canyon. Expecting an attack, the Confederacy set up an ambush, deploying OG-9 homing spider droids to decimate the Republic battalion.
The remnants of K'Kruhk's force managed to reach the end of the canyon, and destroyed the battleship-base.