A valley is a low area of land between hills or mountains, often with a river or stream running through it. Valleys can be formed by various natural processes, such as erosion from water or glaciers. They are usually fertile and provide a great environment for plants and animals, making them important for agriculture and biodiversity. Many famous valleys, like the Grand Canyon in the United States or the Rift Valley in Africa, attract tourists and nature lovers. Valleys can also be home to human settlements, where people build towns and farms, taking advantage of the rich soil and water resources available.