Rock Cairns (U.S. National Park Service)

What Are Cairns? And Why Should You Leave Them Alone?

Why You Shouldn't Stack Rocks On Hikes And What To Do If You See Them

Don't Move Rocks! Friends of the Smokies

I Didn't Know That!: Rock Cairns (U.S. National Park Service)

What The National Park Service Advises About This Common (And Controversial) Practice

Please don't stack rocks on your next hike. Here's why. - Lonely Planet

STOP BUILDING CAIRNS Ecology for the Masses

Rock balancing - Wikipedia

See a Rock Cairn? Push It Over, Yosemite National Park Says

The secret life of rock cairns - Wilderness Magazine