Spelunking is a sport which involves exploring caves. In addition to being recreational, spelunking can also have scientific and cultural value; it may uncover, for example, new animal species or archaeological sites which could be of interest. You may also hear spelunking referred to as “caving,” and some people make a distinction between amateur spelunkers and professional cavers, reserving “caver” for skilled professionals, rather than casual enthusiasts.

People have been exploring caves for thousands of years, for a variety of reasons. Some cultures have had mystical associations with caves, viewing them as locations with a deep connection to the Earth, since they run beneath the Earth's surface. Others have viewed caves with superstition, or used them for cultural rituals such as burials. Humans have also used caves for shelter and habitation.

In a typical spelunking session, people gear up, locate a cave, and go inside with the intention of exploring as much as possible and admiring the natural features of the cave, such as rock formations and underground rivers. Spelunkers usually go in groups for safety, and conscientious spelunkers pay attention to warnings about areas which may be archaeologically or ecologically fragile, taking care to avoid these locations. If a cave has not been mapped before, spelunkers may also take mapping data and notes for the benefit of future explorers.

Some special gear is required for safe spelunking. Many people like to wear heavy-duty overalls, as this sport can get quite dirty, along with a hard hat, to protect their heads from falling debris. Climbing supplies like ropes, anchor points, and carabiners are often necessary, as are heavy-duty flashlights and glow sticks to navigate in the dark. Many spelunkers also take GPS equipment, long-range radios, and food and water supplies in case they become lost or trapped.

Depending on the size and condition of a cave, spelunking can be quite dangerous, or very safe. It is usually a good idea to go out with someone more experienced, especially in the beginning, to ensure that safety hazards are identified and dealt with. Some spelunking and caving associations welcome visitors on their trips, and post information for people who are curious about joining. It is also possible to pay for guided spelunking trips which are supervised by professional cavers for safety.

Like all outdoor sports, spelunking is best undertaken with at least one buddy. Conditions can change rapidly in a cave, even if it's one which has been explored and navigated numerous times before. Having a buddy along can be extremely important if there is an accident.