By Travis and Deena
Canyons are formed by erosion from rivers over many years. They start as just rivers, but over time the rivers wash away the rock under them, and eventually they get deep enough that they become canyons.
A famous canyon you can visit is the Grand Canyon, in Arizona.
The Grand Canyon
The Grand Canyon in Arizona USA
Hornli Ridge in the Matterhorn Mountains in Switzerland
Royal Gorge in Canon City Colorado