The air was still when I woke at dawn on a cloudless morning in Great Sand Dunes National Park and Preserve late last summer. Instead of drifting back to sleep in the dim light, I decided to unearth myself from my sleeping bag and wander about. Only a few other visitors were starting to stir as I glided out of the campground into a high meadow and eventually onto the dunes, which rise like castles out of the high desert.

The sun was shining on the mountains, and layers of dusty pink and blue swathed the sky above the horizon. The tracks of nocturnal critters had blotted out the human footprints from the previous day, and the diurnal animals were just waking up. I passed a deer grazing and inadvertently scared some birds from their roosts. A single fly buzzed by.

Great Sand Dunes is known as one of the quietest places in the United States. When I stopped to listen that morning, there were moments of profound silence in which my ears strained to hear anything at all. Sometimes the only noise I could pick up was the sound of my own breath. It was overwhelmingly peaceful—but my mind kept wandering back to my experience of the park the night before.

My husband, Andrew, and I had arrived around 7:30, just as darkness was falling. The low sun painted crisp lines on the dunes, the tallest in North America. Because of its reputation for noiselessness, I had anticipated a blissfully mellow evening, but a busload of teenagers arrived at the exact same time we did. As we walked across a wide, flat river plain, up undulating foothills, and ultimately up High Dune, the kids’ shouts and shrieks reverberated across the sand.

The auditory intrusions irritated us; after all, we’d come to the park to experience the wilderness and expansive silence. Walking those dunes with a bunch of loud teens felt akin to seeing the granite walls of Yosemite National Park or vistas of the Grand Canyon marred by graffiti, but eventually we were able to laugh at the absurdity of it. The anticipation of the quietness—in other times, a refuge of serenity—made the disturbing power of human racket all the more obvious. The unending din of adolescents followed us nearly to the top of the dune, until the sound of the wind blasting over the ridge finally overcame it.

Illustration by Sarah Maxwell

I was never aware that I needed quiet in my life until roughly 15 years ago, after I moved to Colorado. I grew up an introvert in a clamorous family in big Eastern cities, and noise was omnipresent. When I moved west and suddenly had out-the-back-door access to the mountains, I felt like myself in ways I never had before.

Several years ago, an editor asked me to report and write an article on a series of groundbreaking sound maps created by the National Park Service’s Natural Sounds and Night Skies Division, which is based in Fort Collins. Using a complex algorithm, the maps illustrate predicted median sound levels across the United States on a typical summer day—and also estimate what the country would sound like without human beings.

As it turns out, Colorado is exceptionally suited to a study of silence. On the division’s maps, the Centennial State is part of an expanse of quietude that stretches across the Rocky Mountains and the Southwest, thanks to relatively low population densities and fewer roads compared to the more developed coasts. Even the natural conditions here are hushed because of the arid climate: There’s less rushing water, less rustling foliage, and fewer chirping, murmuring critters. In some areas of the state, like Great Sand Dunes, the ambient sound conditions have clocked in at less than 10 decibels, quieter than the very soft sounds of a calm person breathing.

Natural quiet, which can be defined as the absence of man-made sounds, is sometimes thought of as a null or a void, but it can be a valuable asset unto itself. In addition to reducing stress, studies suggest that time spent in silence encourages neurogenesis, or cell growth in the brain, in mice. Research has also found that human beings typically prefer nature sounds of wind, water, and creatures over artificial noise like traffic and industrial activities, and natural tones can reduce anxiety, stress, and even postsurgical pain.

In surveys, national park visitors cite natural sounds as part of the unique draw of the protected lands. Kurt Fristrup, branch chief for science and engineering at the Natural Sounds and Night Skies Division, told me the agency developed the sound maps to understand noise sources both inside and outside of the parks so they could better protect the soundscapes. “Parks can serve as environmental sentinels to help us perceive what’s going on in the broader world,” he says. “They can serve as classrooms or refugia where we can learn things and explore aspects of being human that are otherwise inaccessible to us in the built environment.”

There are growing threats to natural quiet, though—not only in parks but across the country. And perhaps especially in Colorado, where pockets of natural quiet are arguably one of our most under-recognized resources. On the sound maps, Denver is painted an electric yellow, indicating high noise levels. Colorado’s population is expected to grow from about 5.6 million in 2017 to 8.7 million by 2050, and construction and traffic noise will rise along with it. Because it’s in the middle of the country and has a big international airport, Colorado also hosts an outsize amount of air traffic, which can disturb even the quietest and most remote places.

Fristrup suggests another possible concern for humans: learned deafness. “Our ears are capable of hearing sounds that are a million times softer than relaxed human speech,” he says. “If you live in an environment where most of the incoming sounds are irritating or annoying, you can learn to just shut it off. There’s a real potential for shifting baselines in our perception.”

This is in part why the Natural Sounds and Night Skies Division partners with Colorado State University on a program called the Listening Lab, which helps individual parks understand their soundscapes so they can make management decisions. The program gives students an opportunity to learn about acoustic ecology, but it also schools them in something more intangible—the art of listening.

In a nondescript room in the basement of CSU’s Wagar Hall, undergraduates sit at computer stations clad in noise-canceling headphones, tuning in to faraway places. They have been rigorously trained to pay attention to both natural and man-made sounds, from birdsongs to car motors, and to assign codes to 10-second intervals of recordings made in various national parks. Eventually, Jacob Job, the manager of the lab and a research associate, collects the data into reports on each park’s soundscape.

This year, the students are analyzing recordings collected in Denali, Gates of the Arctic, and Grand Canyon national parks, among others. “This job has changed the way I think about everything,” CSU senior Elena Gratton told me. She has worked in the Listening Lab on special projects for Yellowstone since she was a freshman. “Walking through campus, I’m hearing the birds and the bees and the grass and the wind in the trees. There’s still so much human noise on campus, but it’s allowed me to listen to those natural sounds so clearly. It’s wild, and it’s awesome.”

Several years ago, I embarked on my own immersion into the practice of listening when I signed up for a five-night silent meditation retreat at Kelly Place, a bed-and-breakfast and retreat center in McElmo Canyon, in the southwestern corner of Colorado. I had never done anything like it. Although my family and friends didn’t explicitly say so, many seemed to think it was eccentric. “Wait, no talking? Like, at all?” my neighbor asked with an arched eyebrow. “Like, not even to say ‘excuse me?’ ” Nope, not even to say excuse me.

McElmo Canyon is one of the Four Corners’ rare verdant river valleys, and farms and vineyards dot its lush floor. On the higher slopes, wind and water have carved slickrock into undulating cliffs and slopes. For centuries, indigenous people lived and passed through here, and their kivas, potsherds, and petroglyphs remain. Kelly Place abuts Canyons of the Ancients National Monument, a large, remote, and relatively lonely park.

While it felt natural not to talk as I hiked by myself in the canyons, it felt odd to remain silent around the 40 other participants. No one made eye contact, and we all sat at long tables at mealtimes, chewing and staring at our plates. The schedule was demanding: We practiced sitting and walking meditation all day, from before dawn to after dark, passing each other like zombies, eyes downcast. I wondered what I was doing around all these weirdos.

But soon enough, I began to see the value of the tranquility. When I no longer needed to pull myself together to greet or interact with other people in any way, something in me relaxed. The outer quiet began to invite an inner quieting. And in the stillness, I began to see the undercurrents of my mind, the things I generally pushed beneath the frothy, churning surface of my daily life. I noticed patterns, like the way I hold myself to impossible standards, the petty judgments I have of myself and others, and the fixations on trivialities, like what I might be having for lunch. It wasn’t always easy, but by the end of the retreat, my mind had settled, and I felt a sense of peace and lucidity incomparable to anything I had ever experienced before.

On the way home, I turned on the radio and a song I had listened to many times filled the car. It was the same song as it always had been, but I was listening with a new mind. It felt as if my entire body received the music, not just my ears and my brain. And the retreat changed more than my relationship to sound: As I re-entered my daily routine, the inner quiet allowed me to begin to see my life and habits with fresh eyes and powerful clarity. Not long after, I signed up for another retreat. While it had once seemed crazy to commit to silence, I saw how it actually made me more sane. Now, it seemed crazy not to.

Although it may be considered radical to embrace silence for days or weeks at a time, human beings have recognized the value of soundless solitude as a tool for self-exploration for millennia, from Indian yogis meditating in caves to Benedictine monks, who maintain silence for hours every day. Quiet, along with the sweeping open space of the high desert, is a large part of the reason why Crestone has become an international destination for spiritual seekers. (That, and the fact that in the late 1970s, a wealthy couple started granting land to established religious orders.) Today, Crestone locals claim the town is the largest interfaith community of its kind in North America. Stupas, temples, retreat facilities, a hermitage, an ashram, and other spiritual centers sit on this remote western flank of the Sangre de Cristo Mountains overlooking the vast farmland and open space of the San Luis Valley.

The San Luis Valley. Photo courtesy of RGB Ventures/SuperStock/Alamy Stock Photo.

“We here in Crestone like to think that silence is our greatest commodity,” says Elizabeth Mattis-Namgyel, a Buddhist teacher and author of The Power of an Open Question: The Buddha’s Path to Freedom. A retreat master at Longchen Jigme Samten Ling, Mattis-Namgyel says people migrate to Crestone with grandiose ideas for what they might gain from spiritual practice and living in this beautifully desolate locale, but then they become daunted by the sheer openness and quickly leave. “It can be so overwhelming, the space and the quiet,” she says. “But you learn to relax in it.”

On a recent weekend trip, Andrew and I passed through Crestone, stopping to visit some of the spiritual centers that are open to the public. We chatted with yogis at the Hindu ashram and silently walked about their temple. We strolled the peaceful grounds of a Zen center and tiptoed through the airy chapel at the Carmelite hermitage. The windswept high desert seemed pleasantly calm to me, but not to Andrew. “Seems like a really lonely place,” he said as we walked out of the chapel.

I later asked Mattis-Namgyel about the isolation. Starting in the late 1990s, she undertook a seven-year retreat here in Crestone and spent two years of it in almost complete silence. From her cabin windows, she would look over the valley every day. In the beginning, she found herself looking northward to Mt. Princeton and the other peaks because the mountains somehow felt less isolated than the enormous hazy valley to the south. But over time, her gaze inched toward the San Luis Valley, as if she became ready to experience the emptiness and the possibly frightening feelings it might evoke. In turn, she said, the willingness to be with the discomfort opened her mind and made her feel more connected—and, perhaps paradoxically, less alone.

Over the years, silence has gradually evolved for me, from an alien concept to a good friend. I’ve attended several monthlong silent retreats, and I regularly head into the wilderness to escape the busyness of modern life. But this summer, I experienced a different aspect of quietude on a weekend backpacking trip into the La Plata Mountains in southwest Colorado.

The La Platas are a small but rugged range, short on people and full of talus slopes and spiky summits. One night my friends and I camped in a patch of shady duff beneath spruce and fir trees not far from the Colorado Trail. In the hours before dawn, I woke up. Chelsea, my tent-mate, was asleep, her face still. I got up and out of the tent and looked around. The moonlight bathed everything in a surreal platinum glow—the old trees and their canopies, the stumps and the boulders. Nothing stirred, and the stillness felt eerie, portentous.

I gravitate to places like this for their serenity, but that night the silence somehow felt too quiet. Perhaps the sound of the wind battering the trees or blowing across rocky slopes would have at least given me some reference point, some way of locating myself in the greater context of things.

I scurried back into the tent and zipped up my sleeping bag, my ears pricking at the faintest traces of sound—my breath, the crinkle of nylon against my skin. It was as if my brain was scanning the noiselessness for threats. In the morning, Chelsea told me she too awoke in the middle of the night and noticed the stillness—and heard footsteps. She couldn’t quite tell if it was a deer or a human being. She lay still, listening, spooked. Whatever it was, it passed.

The experience made me wonder if we as human beings are conditioned in some primal way to fear silence, both internally and externally. When I got home from that trip, I looked into whether fear is a common response to silence. I found a 2013 study by a group of Swedish researchers in which participants relaxed in a virtual reality forest after performing a stressful task—in this case, a math problem and a presentation. One group heard piped-in nature sounds, while another group heard nothing at all. The former experienced a decrease in stress, but the researchers were surprised to see that some of the participants in the silent group reported a feeling of anticipatory fear, as if they expected something threatening to appear.

When insects and small mammals fall silent, it is often a sign that a predator is close. Researchers have theorized that humans have adapted to tune in to these environmental signals and expect, for example, a pouncing mountain lion when it’s quiet. Today, the predators stalking a silent forest are often us. I’ve noticed that if I head way out into the woods, lie down in a remote spot, and stay still, a symphony of life rises. It’s as if the surrounding creatures eventually forget I’m there and return to their daily lives. I have heard the flutter of bird wings right over my face.

In some cases, a lack of sound might also indicate that a landscape is barren of food—and therefore life. Ironically, human beings can cause this kind of unnerving silence through our own environmental destruction. Freshly clear-cut forests are often unnaturally quiet because wildlife, like birds, have all left. Noise pollution is no exception. One influential study, published in PNAS in 2015, found that car noise piped in through speakers in a forest—a so-called “phantom road”—caused a more than 25 percent decrease in the overall number of birds, as they avoided the area.

Numerous organizations work to lessen noise pollution; however, a new Los Angeles–based nonprofit is taking a different approach by preserving the quiet itself. Quiet Parks International (QPI), launched in April, is certifying exceptionally quiet parks, trails, communities, and other places in an effort to save natural quiet as well as preserve unique auditory wonders. “Quiet is a basic and essential human need,” says Gordon Hempton, an acoustic ecologist who co-founded QPI. “If natural quiet becomes lost, we will be something else, as a culture, as a species.”

Hempton believes the quiet places that remain can act as refuges for people bombarded by noise in their daily lives and as reminders of soundscapes that were once a quotidian human experience. This year, QPI certified Rio Zabalo in Ecuador as its first official wilderness quiet park. Great Sand Dunes is on the nonprofit’s short list and likely will become the United States’ first wilderness quiet park early next year.

This fall, QPI staff went to Great Sand Dunes to run preliminary evaluations of the sound environment. The park passed a test in which 15 minutes go by without any man-made sounds arising, at a time between one hour before sunrise and two hours after sunrise. Now the park must pass a more rigorous and technical analysis.

Hempton visited the dunes many years ago and luxuriated in the quiet and unique soundscape. In talking with Hempton, I was reminded of my own perhaps anomalous experience at Great Sand Dunes. Hearing that cacophony of teenage voices in potentially one of the quietest places in America seemed poignant, even emblematic.

I wondered if one of the greatest threats to quiet is simply our own obliviousness to it. Unlike forms of material pollution, sound doesn’t leave a residue. In theory, we could clean it up right away. And in a sense, quiet always exists beneath all of the racket, no matter how deafening. It lives in the spaces between our words, the clanking of machinery, the bleeps and bloops of devices, and all of the whirs and bangs of our industrial world. It simply seems like we have forgotten how to listen for it.