• karst
    China's Stone Forest karst formation is a national park.

    Underground Rivers
    Underground rivers, also known as subterranean rivers, flow at least partly beneath the surface of the Earth. Many underground rivers are part of a karst landscape, where eroded limestone often creates caves. Underground rivers may emerge at sinkholes or above ground, as the karst landscape gives way to soil.

    Karst is an area of land made up of limestone. Limestone, also known as chalk or calcium carbonate, is a soft rock that dissolves in water. As rainwater seeps into the rock, it slowly erodes. Karst landscapes can be worn away from the top or dissolved from a weak point inside the rock.

    Karst landscapes feature caves, underground streams and sinkholes on the surface. Where erosion has worn away the land above ground, steep rocky cliffs are visible.

    Shilin is a karst formation in southern China. In Chinese, shilin means stone forest. Shilin got its name because the tall rocks that formed due to erosion look like stone trees. Shilin is part of a larger karst landscape called the South China Karst, which spreads across the Chinese provinces of Guangxi, Guizhou, and Yunnan.

    In Mexicos Yucatn Peninsula, you can find cenotes, which are karst sinkholes that have filled with water. Sometimes, cenotes connect to waterways underground. Mexicans and tourists use the cenotes as cool, pristine swimming pools.
  • Term Part of Speech Definition Encyclopedic Entry
    calcium carbonate Noun

    chemical compound (CaCO3) found in most shells and many rocks.
    cave Noun

    underground chamber that opens to the surface. Cave entrances can be on land or in water.
    cenote Noun

    natural sinkhole or reservoir where groundwater is available.
    chalk Noun

    a soft mineral. Also called limestone and calcium carbonate.
    cliff Noun

    steep wall of rock, earth, or ice.

    		 Encyclopedic Entry: cliff
    dissolve Verb

    to break up or disintegrate.
    erode Verb

    to wear away.
    karst Noun

    landscape made of limestone.

    		 Encyclopedic Entry: karst
    landscape Noun

    the geographic features of a region.

    		 Encyclopedic Entry: landscape
    limestone Noun

    type of sedimentary rock mostly made of calcium carbonate from shells and skeletons of marine organisms.
    rock Noun

    natural substance composed of solid mineral matter.
    seep Verb

    to slowly flow through a border.
    Shilin Noun

    karst formation in southern China. Also called the Stone Forest.
    sinkhole Noun

    hole formed in a rock or other solid material by the weight or movement of water.

    		 Encyclopedic Entry: sinkhole
    stream Noun

    body of flowing water.

    		 Encyclopedic Entry: stream

Websites

Credits

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Writers

Kim Rutledge
Melissa McDaniel
Diane Boudreau
Tara Ramroop
Santani Teng
Erin Sprout
Hilary Costa
Hilary Hall
Jeff Hunt

Illustrators

Tim Gunther
Mary Crooks, National Geographic Society

Editors

Kara West
Jeannie Evers, Emdash Editing

Educator Reviewer

Nancy Wynne

Producer

Caryl-Sue, National Geographic Society

Sources

Dunn, Margery G. (Editor). (1989, 1993). "Exploring Your World: The Adventure of Geography." Washington, D.C.: National Geographic Society.

Last Updated

Jan. 21, 2011

User Permissions

For information on user permissions, please read our Terms of Service. If you have questions about licensing content on this page, please contact natgeocreative@natgeo.com for more information and to obtain a license. If you have questions about how to cite anything on our website in your project or classroom presentation, please visit our FAQ page.

Media

Some media assets (videos, photos, audio recordings and PDFs) can be downloaded and used outside the National Geographic website according to the Terms of Service. If a media asset is downloadable, a download button appears in the lower right hand corner (download) of the media viewer. If no button appears, you cannot download or save the media.

Text

Text on this page is printable and can be used according to our Terms of Service.

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.