Caves of San Diego
[From Desert USA:] Some caves offer easy exploration, while others require tight crawls, challenging climbs or dangerous descents. Caves can be cold, dark and damp. They can also be dusty-dry, muddy or completely filled with water. All are dark and many can be extremely dangerous, especially without proper gear, knowledge and experience.
If you are interested in caving, experienced local groups can provide invaluable resources. Membership involves NSS membership, which includes newsletters, knowledge of those who have been there before, maps, fellowship and safety.
Serious cavers devote a good deal of time to training and planning. Acquiring approriate climbing gear and practicing how to use it is a preoccupation of local grottos. Mapping, photographic documentation and protection of local caves is also part of their charter.
This passage has been borrowed from Desert USA because we could not have descibed these adventures any better. Here is a link to the article. You will find more information and a serious list of the gear you need to have and know how to use!