According to National Geographic, erosion occurs when the particles that have been broken down by weathering are carried away to other areas. Erosion can take place via wind, rain, plants and animals, moving water and even moving ice.
Erosion is a slow and gradual process that can occur over thousands and millions of years. It changes the landscape by wearing down the tops of mountains, filling in valleys with debris carried by rainfall and even making rivers appear and disappear. Water is the most powerful erosive force, and a large powerful river can move huge rocks and can push back waterfalls.