"If you can only see one thing here, see the Big Room in Carlsbad Cavern," advises Bridget Litten, the park's former public affairs specialist. "Allow an hour and a half, and if you have more time and are in good physical condition, take the Natural Entrance Route into the cave, which has a 750-foot descent and is a bit strenuous."

The potential for scientific discoveries from caves is tremendous, Litten says, adding that research is underway in Lechugilla Cave that may eventually provide a cure for certain types of cancer. "They're collecting microscopic life forms -- bacteria that survive without sunlight and secrete an enzyme that appears to be able to kill breast cancer cells without harming healthy human cells."

Litten says that park visitors should not miss out on the aboveground attractions, such as the evening bat flight, and the 9 1/2-mile scenic drive, which provides panoramic views of the surrounding desert. "A good time to take the drive is late afternoon or early evening after the visitor center has closed and before the bat flight program has begun," Litten says, adding that "it's usually cooler then, too."

She also suggests a picnic at Rattlesnake Springs, a "birders' paradise," she calls it, and adds that those who want to experience the Chihuahuan Desert without any crowds should consider hiking the park's backcountry, which less than 1% of the park's visitors do.

Although this park is devoted primarily to the work of nature, observing human activities in the caves is part of the Carlsbad Caverns experience. Throughout the main cavern, you'll see evidence of human use (and misuse) of the caves. Those taking the guided Lower Cave tour will see artifacts left by early cave explorers, including members of a 1924 National Geographic Society expedition.

Cave Exploration

Carlsbad Cavern (the park's main cave), Slaughter Canyon Cave, and Spider Cave are open to the public. Experienced cavers with professional-level equipment can request permission to explore some of the park's other caves.

Most visitors head first to Carlsbad Cavern, which has elevators, a paved walkway, and the Underground Rest Area. A 1-mile section of the Big Room self-guided tour is accessible to those in wheelchairs (no wheelchairs are available at the park), though it's best to have someone along to assist. Pick up an accessibility guide at the visitor center.

Main Carlsbad Cavern Routes

Most visitors see Carlsbad Cavern by taking the following three trails, all of which are lighted and paved and have handrails. However, the Big Room is the only one of the three that's considered easy. The formations along these trails are strategically lit to display them at their most dramatic.

Big Room Self-Guided Tour -- Considered the one essential of a visit to Carlsbad Caverns National Park, this trail meanders through a massive chamber -- it isn't called the Big Room for nothing -- where you'll see some of the park's most spectacular formations and likely be overwhelmed by the enormity of it all. Allow about 1 1/2 hours. 1.25-mile loop. Easy. Access: Visitor center elevator to Underground Rest Area, or Natural Entrance Route.

King's Palace Guided Tour -- This ranger-led 1 1/2-hour walk wanders through some of the cave's most scenic chambers, where you'll see fanciful formations in the King's Palace, Queen's Chamber, and Green Lake Room. Watch for the Bashful Elephant formation between the King's Palace and Green Lake Room. Along the way, rangers discuss the geology of the cave and early explorers' experiences. Although the path is paved, the 80-foot elevation change makes this more difficult than the Big Room trail. Children under 4 are not permitted. 1-mile loop. Moderate. Access: Visitor center elevator to Underground Rest Area.

Natural Entrance Route -- This moderately strenuous hike takes you into Carlsbad Cavern on the same basic route used by its early explorers. You leave daylight to enter a big hole, then descend more than 750 feet into the cavern on a steep and narrow switchback trail, moving from the "twilight zone" of semidarkness to the depths of the cave, which would be totally black without the electric lights conveniently provided by the Park Service. The self-guided tour takes about 1 hour and ends near the elevators, which can take you back to the visitor center. However, it is strongly recommended that from here you proceed on the Big Room Self-Guided Tour, which is described above, if you have not already been there. 1.25 miles. Moderate to strenuous. Access: Outside visitor center.

Nearby Attractions

Many visitors to Carlsbad Caverns also spend time at nearby Guadalupe Mountains National Park.

We also highly recommend spending a few hours at Living Desert Zoo & Gardens State Park, located on the northwest edge of the city of Carlsbad off U.S. 285 (tel. 575/887-5516; www.nmparks.com), where you'll get a close-up look at the plants and animals of the Chihuahuan Desert. A 1.3-mile trail meanders through the various habitats that make up the desert, from sand hills, to gypsum rock formations, to the mountainous pinyon-juniper zone. Animals here include elk, mule deer, pronghorn, black bear, bison, mountain lion, badger, and porcupine.

There's also a small herd of javelina, named for their short, javelin-sharp tusks, that enjoy a meal of tasty prickly pear cactus, spines and all. There's a Reptile House, an aviary, and a pond that attracts migrating ducks and geese.

There are numerous plants of the Chihuahuan Desert and an amazing collection of cacti and succulents from around the world -- those hardy species that can endure extreme heat and cold, sandy soil, and very little water.

From Memorial Day weekend through Labor Day weekend, the park is open daily from 8am to 5pm, with the last entry to the zoo at 3:30pm. Hours the rest of the year are shorter, and it is closed Christmas Day. Especially in summer, it's best to get to the park during the cooler morning hours, when the animals are more active. Admission costs $5 for those 13 and older, $3 for children 7 to 12, and is free for kids under 7.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.