Understanding the contention surrounding one of humanity’s most ancient art forms: rock-stacking. 

Hike far enough on just about any trail in the world and you’re certain to spot what may at first seem like benign additions to the landscape: collections of stones placed on top of each other to form impromptu sculptures.

Some call them cairns. Others favor more colorful terms like “stone balancing” or “prayer stone stacks.” Whatever the name, the act of stacking rocks atop each other is as ancient as it is ubiquitous. And over the course of the past decade or so, for better or worse, it has been becoming even more popular thanks to social media.

What many don’t know, however, is that it is a practice rife with controversy, especially as it finds its way into national parks and other protected areas. Depending on whom you ask, rock-stacking is either a crucial navigational device, an environmental menace, or even a rewarding mindfulness practice. 

So, is rock-stacking as harmless as it seems? Let’s dig in.

Close-up of rock cairns created by visitors in Joshua Tree National Park
Rock cairns created by visitors in Joshua Tree National Park, California © Pam Susemiehl / Getty

When a pile of rocks points the way home

These days, most rock stackers do it as a way to mark a trail, especially in less frequently navigated backcountry. Others claim the act of slowly and deliberately stacking rocks can be another way to practice mindfulness. 

While its meditative benefits are open to interpretation, it is true that a well-placed cairn can save lives. For that reason, Michael Larson, a public information officer with the U.S. National Park Service doesn’t recommend kicking them over when you come across them, despite what you see on Tik Tok or online hiking forums. In fact, he points to certain locations where cairns are part of official policy. “Carlsbad Caverns National Park uses cairns for safety to assist visitors with finding trails in remote areas of the park's backcountry,” he said. Along volcanic landscapes in the jagged terrain of Hawaiʻi Volcanoes National Park, where cairns are still known by their traditional name ahu, they’re also sometimes set up by park rangers, particularly in the most remote sections. 

So, before you start kicking cairns over, consider why they were set up in the first place. If a park ranger did it there’s a good chance it was done to save lives.

From tradition to trend

Cairns were our ancestors’ first foray into building structures: pile some rocks on top of each other and you have the beginnings of a shelter or a food cache, for example. In Mongolia, cairns marked burial sites in cemeteries, and in Tibet they were used in Buddhist ceremonies to call in good fortune and balance out conflicting energies. Prior to the invention of lighthouses, cairns warned sailors away from Norway's jagged fjords. They’ve been placed as landmarks on hilltops in Scotland and as trade route markers for sled dogs plowing through the Alaskan wilderness. For a time, they were even a key tool in a strategy for hunting bison, used by a variety of indigenous groups from the Rocky Mountain foothills to deep in the Dakota plains. 

Today, the popularity of rock cairns has less to do with utility and tradition and more to do with social media. That’s the opinion of the Colorado-based rock-stacking artist, Michael Grab, who goes by the moniker Gravity Glue

“It really started to blow up between 2014 and 2015,” he said, speaking of the trend towards stacking rocks in gravity-defying formations and posting the photos onto social media. “Then it exploded into this international art form, and what was maybe a handful of practitioners became hundreds.” As a result, others followed, stacking rocks on beaches, on hiking trails, and, much to the chagrin of conservationists, in places where visitors are specifically asked to “leave no trace.”

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Cairns mark the trail from Elephant Hill to Chesler Park in Canyonlands National Park, Utah
Cairns mark the rugged trail in Canyonlands National Park, Utah © jtstewartphoto / Getty

The arguments against cairns

Besides potentially confusing lost hikers, critics say rock-stacking can be culturally insensitive to past and present residents of the area. They also point to the cumulative effects disruptions can have in ecosystems underfoot. On mountain trails, critics have pointed out that when even a few stacked rocks fall, it can trigger cascades that could hurt unsuspecting hikers below. Even when they’re arranged to be completely safe, many nature photographers and other lovers of the outdoors simply say they’re an eyesore, distracting from the untouched environment.

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A hand setting a stone atop a cairn stone pile
Official rules around cairn-building can vary depending on location © Peter Lourenco / Getty

Read the rules

While the National Park Service at times employs rock-stacking as part of its route-marking system, the agency prohibits people from adding their own cairns to the landscape in most parks. Just like carving initials into a tree, leaving behind trash in a campground, or spray-painting your name on a rock face, rock-stacking in most (but not all) National Parks is punishable under the same laws that protect these places against vandalism and littering. 

To differentiate official markers with impromptu ones, the National Park Service recommends visitors check with park rangers for information about the design and materials used in the creation of any cairns along trails. 

“We always encourage visitors to have a plan to find their way in park wilderness.” Jonathan Shafer, Zion National Park’s public affairs specialist, said, emphasizing that cairns should never be your only navigation tool. “Especially in remote areas, it’s important to have wayfinding tools like maps and a compass or GPS to navigate.”

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A rock cairn in the middle of a river
While building cairns for photos is popular, it's best to return the rocks to where they were once you're done © Daniel Hanscom / Getty Images / iStockphoto

So, is rock-stacking bad?

On its own, rock-stacking isn’t always a harmful practice, though it can be. For many people, it can also be therapeutic or even an artistic outlet. In the most remote locations on Earth, cairns can literally save lives. Just make sure to learn about and follow local regulations and don’t do it in national parks or other protected lands. And if you do feel the urge to sit on the side of a trail or on a riverbank and build something, when you’re done, be like Grab, who follows a leave no trace policy, even when he’s building his improbably stacked rock towers. “I take it down when I’m finished to close the loop,” he said.

You might also like:
What it means to Leave No Trace: 8 principles to be more mindful outdoors
15 unforgettable experiences in US national parks
The best wildlife experiences in the USA 

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