A valley is a low area of land that is located between hills and mountains and is usually crossed by a river or stream or other types of tributaries. The valley is usually formed when a river or glacier moves through a geological region.
More extensive valleys (known as rift valleys) can form at tectonic plate boundaries when the plates move apart. The best-known rift valley on Earth is the “Great Rift Valley System” in Africa. The region is geologically active and features volcanoes, hot springs, geysers, and recurring earthquakes.
