The hiking trail was not rigorous. A rattlesnake did catch me by surprise, sliding quietly out from the underbrush less than a foot away. Even then, he acknowledged my presence and slithered onward with better things to do. I hadn’t noticed him because I was fixated on the trail’s exhibit, a single odd butte, consisting of light green and yellow hexagonal basalt columns towering high above the surrounding ponderosa pines.

Known as Devils Tower to the Park Service—and to many others as the place aliens visited in Close Encounters of the Third Kind—Native Americans first named it Bear Lodge, where The Great Spirit saved girls from a bear, taking them to the stars where they became the Pleiades. As I hiked, colorful prayer cloths tied to branches demonstrated that it remains a sacred place.

I’m not religious or spiritual, but I understand Bear Lodge’s appeal as a spiritual space. Because I’m a non-believer, people ask me how I can enjoy nature’s beauty without a God; faith or spirituality is not a requirement for enjoying nature. For me, these encounters with our national parks and monuments feels like a visit to an art gallery, showcasing collaborating artists from the geological, hydrological, glacial, and evolutionary schools.

Earlier this year, I took an 18-day road trip to the northwest—covering approximately 5,232 miles and seven national parks and monuments—which offered many opportunities to enjoy their collected body of work. This was a gallery crawl, so to speak. Each park or monument highlighted the unique signatures, strokes, and color palettes of these impersonal artists. Each left me continually in awe.

The trip was bookended by short visits to what are called “badlands,” specifically those found in Badlands National Park and Theodore Roosevelt National Park. Badlands is a term used for rugged desert terrain eroded by millions of years of wind and water.

Once a shallow sea and then a tropical forest, Badlands National Park in South Dakota is now a wide visual piece, decorated in spires and hoodoos, with exposed stratum laid down 75-26 million years ago, inked in pastel pinks, red, and faint orange, and carpeted with green prairies. Roosevelt’s badlands in North Dakota—once a vast swamp—is lush with grasses and a range of vibrant flowers.

These fossil-strewn ancient badlands are built for the imagination—Badlands National Park even has an artist in residence program to help capture that creativity.

The ellipses between these badland visits was filled with lengthier stays at Grand Teton, Yellowstone, and Glacier national parks.

Grand Teton is beautiful, serene, rich in wildlife, and highly accessible. Almost every turn and educational pull-off centers on the 10 million year old Teton mountain range, a collaborative project involving tectonic plates and glacial activity. Earthquakes along the Teton fault line have dropped the ground almost four times as much as it rose the mountains. Approximately 12,000 years ago, glacial activity carved out space for the blue waters of Jenny and Jackson Lakes.

It was while hiking the Jenny Lake trail, with the mountains in constant view, that I felt I best understood John Muir’s famous words in The Yosemite: “Everybody needs beauty as well as bread, places to play in and pray in, where Nature may heal and cheer and give strength to body and soul alike.”

I understood how the natural and coherent aesthetic of the Tetons could heal. While I don’t believe in souls, if a national park could be a soulmate, then Grand Teton feels like it would be a close first for me.

By contrast, Yellowstone National Park was home to the greatest diversity of exhibits, a jarring mix of arresting pastoral scenes and violence. In many ways, it is reminiscent of an Hieronymus Bosch diptych—in which one panel shows paradise and the other eternal judgement.

The first panel of a Yellowstone diptych was the idyllic—deep greens of pine-tree-lined mountains and swaying prairie grasses hiding sandhill cranes. These places, like Hayden Valley, are home to bison, which trek along an oxbowing Yellowstone River—a river that eventually emerges as a show-stopping emerald waterfall within the walls of The Grand Canyon of Yellowstone. To more fully appreciate this paradise, I parked myself along Yellowstone’s Madison River to picnic and read.

But then there is the second panel of the diptych—one which demands your respect.

The park sits on the caldera of a supervolcano, fueling its 10,000 hydrothermal features of geysers, hot springs, and mudpots. Visit any of these and one is immediately greeted with heat and hydrogen sulfide gas—sometimes called the “smell of hell”—which frequently belches from the bowels of the earth.

The Norris Geyser Basin, created by seismic activity at the intersection of fault lines, is highly acidic and reaches superheated temperatures—known for even dissolving the bodies of careless visitors. More than telling the history of the park, geothermal activity—like the still-shaping limestone terraces found at Mammoth Hot Springs—is like being in the sculptor’s studio.

These hotspots are home to thermophiles—microorganisms evolutionarily adapted for these boiling conditions. These thermophiles are essentially the paints of hot springs, like that of The Grand Prismatic Spring—a rainbow palette, of bright yellows, oranges, reds, and more shades of blue than I knew were possible.

I left this mix of earthly delights and judgment halls at Yellowstone and ascended northward to the celestial Glacier National Park. Glacier is incredibly wild—as in, a grizzly bear will tear you apart wild—but that wild is set within a wonder-inducing world.

The park has one road that cuts through it—the Going-to-the-Sun Road, which is by itself a geological and ecological lesson. True to its name, this road is a winding ascension into the sky, reaching its apex at 6,647-feet at Logan Pass, which sits on the continental divide. I began the day with the sunrise before me and ended it chasing the sunset.

Going-to-the-Sun Road is a tour through Glacier’s sloped peaks, deep valleys covered with evergreen forests, tumbling turquoise rivers, and clear blue lakes—all hewn out over centuries by glaciers, the remnants of which are disappearing fast.

There is no question for me as to why these wonderlandscapes —to borrow the title of John Clayton’s book—have an almost magical or mysterious and spiritual appeal that is ripe for the theological imagination. I understand why these places, and the wonder they imbue, are associated with a divine creator or a spiritual being. But what I see is an astounding natural process that makes life possible and beautiful.

As an education in the skills and technique of an artist can add to the appreciation of a piece, so also can learning more about the natural and scientific world behind the rutted badlands or the rawness of mudpots add to the pleasure of experiencing their beauty.

These breathtaking landscapes remind us that we were once un-domesticated animals fully attached to the land. At one time, we were wild—exposed to the elements, rising and sleeping according the sun, and gathering and hunting for our food. To understand them is to understand ourselves. This is what pushes us out of our hermetically sealed homes and drives our need to return to these natural galleries that tell the earth’s story.

Enjoying the beauty of national parks is a search for our shared humanity.

Whether one is at the Teton mountain range, the high peaks of Glacier, or a bizarre butte made of basalt columns, “we are all, in some sense, mountaineers,” as John Muir also says, “and going to the mountains is going home.”