The Grand Canyon
A canyon or gorge was a geological formation with a deep ravine between cliffs.
Captain Jonathan Archer and Commander Tucker were up to explore a gorge on the southern continent of an uninhabited planet which was five times deeper than the Grand Canyon. (ENT: "The Catwalk")
In 2254, the Enterprise transporter chief Pitcairn beamed the landing party from the USS Enterprise into a canyon on Talos IV to hide them from the survivors on the planet. (TOS: "The Cage")