Valley

A Valley is an area of land, typically at least a few square miles (kilometers) but often hundreds or even thousands of square miles (kilometers), surrounded by higher areas, mountains, or hills.
Valleys are formed by numerous geographical processes, and can result in 'Glacial Valleys' formed millions of years ago by Glaciers, or Rift Valleys, formed by the expansion of the Earths crust due to activitiy beneath the Earths surface.

Famous valleys include:

Death Valley

Grand Canyon

Great Rift Valley

Napa Valley[?]

Rhone Valley[?]

Valley of the Kings

See also: physical geography.