Given the task definition and input, reply with output. You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: NATURAL WONDERS 
Clue: Given its current name by John Wesley Powell, it was called Kaibab, or "mountain lying down" by the Paiutes

the grand canyon