I've visited more national parks this year — during the park service's 100th anniversary — than all the other years previously. I even got a national parks pass for the first time, and I've already got my money's worth.

Yosemite and Yellowstone are spectacular visions of what how dramatic landscapes can be, and Mount Rainier is intimidatingly glorious, and Joshua Tree is an insanity of natural sculpture, light, and shadow-shapes — but there's only one national park that has genuinely shocked me so far.

Carlsbad Caverns is an honest-to-goodness wonder of the world, more so for being hidden under some bland-looking desert landscape. It's the kind of shocking experience that takes months to mull over, and though I adore the other national parks I've been lucky enough to visit, it's Carlsbad that I keep returning to in my daydreams.

Carlsbad Caverns topside. The landscape around Carlsbad Caverns doesn't betray the beautiful caverns below ground. (Photo: Starre Vartan)

I'm not exactly an underground newbie, so my wonder is not due to ignorant surprise at what lies beneath. I studied geology and worked as a geologist for a brief period before turning to writing, and since that time, I've been inside at least a dozen caves and caverns. So I wasn't convinced I would see anything new visiting these caverns, situated in a (very) out-of-the-way part of southern New Mexico, not far from the Texas border. I even wondered why caverns could be considered a national park.

A National Park Ranger at Carlsbad Caverns. National park rangers share important information before you descend into the caverns and are available throughout the underground hike. (Photo: Starre Vartan)

The answer is that Carlsbad is on a different scale from any cavern I've previously seen — and that's one of the reasons it's a national park, though not the only one. While you might get an approximate idea of the size from the well-put-together informational displays in the visitor's center, it's hard to resist the thrilling pull of going down into the caves.

When I visited with my friend and colleague Lindsay Brown (she's the one in the aqua-and-white shirt in the pictures), we slowly walked past the educational info on our way to the cave entrance, and I noted that these were caves formed by limestone and water doing their usual cave-making thing. I took a moment to check out the 3-D overhead sculpture/map. I guessed the trail would take us an hour or so to walk, similar to other caverns I'd been in. Oh, how wrong I was.

The entrance to Carlsbad Caverns. The natural entrance to Carlsbad Caverns (which is also the exit) is the last sunlight you'll see as you descend into the cavern. (Photo: Starre Vartan)

We spent three to four hours inside the caverns, in spaces so vast I felt like I'd been hiking outside all day, yet I'd been underground. And we weren't walking slowly either: It's a 1.25-mile walk into the cave just to access the Big Room (and the same distance to get back), then there's another 1.25-mile walk to see all the features within. We walked a couple of the spur trails a several times — there was so much to see on both sides of the paved track that going one way, you're bound to miss what's on the other side.

Signage at Carlsbad Caverns There's informative signage along the walkways throughout the cavern, so even if you don't know much about caves, you'll learn as you go. (Photo: Starre Vartan)

As you walk, you'll move in and out of large rooms (the largest is 4,000 feet long) and intimate spaces (the size of a small closet), and as you walk deeper into the earth, there are countless details to check out, each of which took thousands of years to develop. It becomes a meditative exercise in observation, a joy of light and shadow, shapes and textures.

A large room in Carlsbad Caverns. Large rooms like this one help you feel like you're walking outside. (Photo: Starre Vartan)

Take some time to stand in front of one or two structures and really look at them — there's so much detail it can become overwhelming at times, just like an art museum. I still remember the intricacies of the stalagmite below as I looked at it for some time, taking a walking break and just admiring it.

Monumental features in Carlsbad Caverns The stalactites and stalagmites are sometimes fat and monumental, and other times as skinny as a pencil, creating lace-like patterns. (Photo: Starre Vartan)

And when you head back out, you'll notice the power of natural light in a way you may have never noticed before. The intensity is dramatic. I felt as if I were leaving a quiet, relaxing, monochrome world, and going back to the almost-too-muchness of the "real world." It was a unique feeling, much like returning back to the United States after spending time in other countries. Being in a cave is travel of a different sort.

Natural light in Carlsbad Caverns. Hiking out of the natural entrance to the caverns, you will spot the exit long before you get close to it; the light is that powerful after having been in darkness for so long. (Photo: Starre Vartan)

A few logistical details:

1. Caves are naturally cool, so even if you're hot and sweaty up top, be sure to bring an extra layer with you. Even though my friend and I walked at quite a clip down into the caverns, as soon as we stopped to take pictures or admire features, we got chilled quickly.

2. Bring water, but don't expect to picnic in the caves — food is not allowed.

3. Enter via the natural entrance instead of taking the elevator if you are physically able. It's an incredible experience as you descend into the darkness, slowly, and it also gives your eyes a chance to adjust. (It can take our eyes 20 minutes or more to fully adjust to darkness, which means you'll still be adjusting for awhile if you take the elevator down, and you'll miss details during that time.)

Detail in Carlsbad Caverns. There are countless small rooms 'decorated' by natural stalactites and stalagmites, as well as huge spaces within Carlsbad. (Photo: Starre Vartan)

4. Give your eyes a chance to adjust, and explain how this works to kids; in our light-polluted world, many adults and kids are never in real darkness (though the caves are lit at a very low level). Unless you or your kids have a genuine vision problem, you don't need a flashlight in the caverns — the human eye is capable of adjusting to very low-light situations. (Imagine how dark it was for most of human history before electric lights were developed.) And a flashlight is a horrible intrusion for others who are trying to experience the caves. Mostly, it seemed as if people were using them as toys, not because they really needed them (probably because they didn't).

5. Go early enough in the day that you'll be able to walk the entirety of the caves; they are extensive and you will want to dawdle at some spots and take it in — certain rooms close earlier in the day.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.