California Underground Online Exhibits - An overview of the formation of caves, cave conservation, photography and wildlife together with local educational resources. Diagrams, pictures and slide shows.
Speleomania - International discussion forums and links to cave-related news items and groups.
The Caving Pages - An introduction to caving, cave types and conservation together with links to many caves and organisations around the world.
World Cave Database - A list of long and deep caves from all around the world. Listed by depth, length and country.
UIS International Speleo Calendar - Events around the world.
U.S. Cavers Forum - Discussion forums including caving, the NSS, the study of speleology, cave conservation & management, bats and gear.
Caving From Spadout - Articles on the terminology, techniques and gear used for caving. Discussion boards, editable information, feedback and links.
Cavechat.org - Discussion forums including cave diving, news, conservation, equipment, photography, rescue and surveying. Hosted by the National Speleological Society.
Bill Storage - Speleology - Photographs and articles dealing with speleology and cave exploration.