Canyons are deep, narrow valleys with steep sides, often formed by the erosion of rock and soil over time, typically by rivers. They can vary in size and shape, with some canyons being just a few feet deep while others, like the Grand Canyon, can reach depths of over a mile. Canyons are found all over the world and can be created through various geological processes, including tectonic activity and glacial movement. They often feature unique ecosystems and can be home to diverse wildlife, making them important for both natural beauty and biodiversity.