If you ever demolished a play date’s block tower as a child, be ashamed no longer.

In a viral Facebook post from July 11, visitors to Yosemite National Park (@YosemiteNPS) were asked to “dismantle and refrain from building rock cairns.”

The nine-second clip, which has garnered over 10 million views, showed a wilderness restoration ranger toppling a huge rock cairn.

The stack, which included more than half a dozen large rocks, was knocked over because it didn’t comply with Leave No Trace ethics, which dictate that humans leave no trace of their presence in the wilderness and respect the creatures that live there.

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“This dramatically oversized cairn is a mark of human impact and is distracting in a wilderness setting,” the caption stated. “Building rock cairns also disturbs small insects, reptiles, and microorganisms that call the underside home!”

Cairns are used for navigation and safety along trails, according to the post, and should be constructed by rangers and trail workers.

“Moving rocks disturbs the soil and makes the area more prone to erosion,” the National Park Service noted. “Disturbing rocks also disturbs fragile vegetation and micro ecosystems.”

A 2019 post on Ecology for the Masses noted that taking rocks from streams and rivers to build a cairn can be particularly devastating.

“Aquatic insects, fish, and amphibians … depend on the crevices and hollows between and under rocks to make their homes,” Adam Hasik wrote. “Additionally, the algae that used to be on the rock can no longer filter the water and provide oxygen to the system, only adding to the problems that are plaguing the water body.”

The 1,169-square-mile Yosemite, first protected in 1864, features countless waterfalls, ancient giant sequoias, and vast wilderness in the High Sierras of California and was visited by 3.7 million people last year.

“Good idea. I wouldn’t have thought of it that way,” one user commented. “Enjoy hiking and be safe.”

Another said, “Have fun hiking. I didn’t know that it has to be dismantled. Thanks for sharing.”

The post also pointed out that visitors to other places should check local recommendations.

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