Ravine

A ravine was a long, deep opening in the ground, resembling a deep and very steep-sided valley.

The Wavis Ravine was a ravine on Pakha. Some Pakhar believed that it was bottomless. Others believed it led to the heart of Pakha, where the Dæmon Mianik'ha lived. (PROSE: Legacy)

The Grand Central Ravine was a geological feature named after the ancient British city of Sheffield. (TV: Bad Wolf)