section_path: Features/Plains and valleys
section_name: Plains and valleys
paragraph_text: Plains and valleys
  
  Wide, flat areas of land are called plains, which cover more than one-third of Earth's land area. When they occur as lowered areas between mountains, they can create valleys, canyons or gorges, and ravines. A plateau can be thought of as an elevated plain. Plains are known to have fertile soils and be important for agriculture due to their flatness supporting grasses suitable for livestock and facilitating the harvest of crops. Floodplains provided agricultural land for some of the earliest civilizations. Erosion is often a main driver for the creation of plains and valleys, with rift valleys being a noticeable exception. Fjords are glacial valleys that can be thousands of meters deep, opening out to the sea.