A canyon is a deep, narrow valley with steep sides, often formed by the erosion of rock and soil over time, typically by a river. Canyons can vary in size and shape, and they are commonly found in mountainous regions. The walls of a canyon can be made of various types of rock, showcasing different geological layers. One of the most famous canyons in the world is the Grand Canyon, located in Arizona. It stretches about 277 miles long and reaches depths of over a mile. Canyons are popular destinations for outdoor activities such as hiking, rafting, and photography, attracting millions of visitors each year.