What is the name of the deepest canyon in the United States?

In which country is the Cotahuasi Canyon located? What is the name of the largest canyon in the world? Which canyon in Arizona, USA is known for its red rock? In which mountain range is the Samaria Gorge, a famous canyon in Greece? What is the name of the canyon carved by the Rhine River in Switzerland? What is the name of the canyon carved by the Verdon River in France? In which country is the Copper Canyon located? In which state is the Waimea Canyon located?