There's something about the underworld that has always fascinated the human mind.  This is why explorers push deeper and farther into the ocean depths, and landlocked folks crawl down cracks and crevices to explore the treasures of the dark.   

Caving, or "spelunking," can be tremendous fun, but can also be extremely dangerous if you don't take some safety precautions. Basic Rules for Caving

• Always tell someone where you are going to be and how long you expect to be there.
•  Never go caving when it's raining -- caves can flood extremely fast.
• Always leave markers to show how to get back.
• Never go alone. 
• Always watch where you put your hands. (There's usually a lot of "bat missiles" down there.)

Proper planning is the most important aspect of your underground journey.  Even though it's supposed to be an exploration, it's still imperative that you ask around and find out if the cave has any surprises that might cause harm to yourself or your fellow moles.  You also need to make sure that you have permission to be in the cave.  Even though everyone around the area says it's OK, that doesn't mean that you have permission to be there.

If you come across a cave on public land and it has bars welded across it, don't try to enter it. The bars are there for a reason.  Usually conservation departments put them up because the cave has an abundance of bats.  State agencies don't want people disturbing bats because they're fragile creatures that eat a lot of mosquitoes, which is fine by me.

Respect the cave.  Don't use spray paint to write your name or to mark your way; marking tape works just as well.  The paint you use will be there forever.

Don't touch the rock formations.  Stalagmites and stalactites take thousands upon thousands of years to form -- one touch of a fingertip can stop its growth because of the oil in your skin.

Lighting

Proper lighting is very important, as known to anybody who's been in a cave and turned off the flashlights, but you don't want to get crazy with it and end up hauling 50 pounds of artificial sunshine around with you.  The flashlights I carry are a Princeton Tec Solo headlamp and a big Mag-Lite.  The combo will illuminate a cavern rather well. If you need to climb something you can pocket the Mag-Lite and still see where you are going with the headlamp.  I also carry the compact Princeton Tec 40 in my pack for a backup.  For added insurance, I carry a chemical light stick and an extra set of batteries.  

The Caving Pack

One thing that I always have with me when I go spelunking is my "caving pack," a small frameless backpack filled with items essential to a safe trip to the depths. 

• First-Aid kit --  This is a must to have along on any outdoor excursion. Since scrapes are a prominent malady of caving I always take plenty of gauze and Band-Aids sealed in a plastic zipper bag.  I also carry in my pack two slender poles about 2 1/2 feet long for emergency splints. (Not many trees grow in caves.)
•  Rope -- You never know what kind of situation you will be getting into, and you might have to climb down something.  Just make sure to check the rope before each trip.  I carry a nylon rope with knots tied into it for easy climbing, and a couple of rock-climbing wedges for a quick way to secure the rope. 
• Energy -- I usually pack some Nutri-Grain bars for a quick source of energy, and I make sure I have plenty of water. 
•  Miscellaneous -- other items to pack include extra batteries, dry washcloth in a Ziploc bag (for cleaning eyeglasses), marking tape and a good sturdy knife. 

Clothing

Don't wear your Sunday best -- old pair of jeans and a t-shirt will suffice, but don't expect to get them clean. You can go with a long-sleeve shirt, but you'll probably get warm and want to shed it after you're in for a while.  So you might as well not worry about getting dirty and hop in because you will walk out looking like a washing machine's nightmare.   

Kneepads are a spelunker's best friend --  they'll save you from a lot of pain. I have come back from a trip without kneepads, and my knees looked like two bleeding beach balls.  For hand protection I wear a pair of cotton gloves, but they don't really protect -- they provide a nice barrier between skin and "bat surprise."

There are two different types of shoes that I wear in a cave.  If I know the cave will be wet and muddy one, I'll take some light hiking boots with a good tread on them.  Usually I just wear wrestling shoes because they're lightweight, good for climbing, and when I get water in them I'm not carrying around 20-pound feet.

Transportation

Of everything that I've told about caving in this article, this is the most important, especially if you have a spouse, or have any qualms about driving home naked.  Take plastic trash bags with you.  I've been on many caving expeditions, and for some reason I still usually forget trash bags.  Now you're probably wondering why anybody would want to take trash bags on a caving foray.  That's easy: to cover the seats of the car.  Taking extra clothes is another solution, but you will usually end up getting the clean clothes dirty trying to switch them. Having Handi-Wipes outside the car ensures everyone can clean their hands before touching anything in the car.

For more information on caving, contact your local conservation department or a spelunking club in your area.