If you go for a hike, you might see some interesting plants, beautiful views, amazing wildlife, and perhaps even a tower of stones built by some hiker that came before you. They are called cairns and some are elaborate, using dozens of stones varying in size, while others are more rudimentary, consisting of just a few big rocks stacked up a couple of feet high. Regardless of how they look, the columns of stones can be rather artistic and a treat to encounter during a hike, however, officials are urging hikers to knock over any cairns that they see.
Park rangers at Yosemite National Park made the surprising ask in a video on their Facebook page, explaining that the cairns break the Leave No Trace ethics that help to conserve the outdoors. The goal of the rules is to respect all the creatures living on the land by not leaving any signs of human impact. Picking up stones and placing them atop one another goes against that. The rangers state that when those cairns are built, it also disturbs the small insects, reptiles and even microorganisms that live beneath the rocks.
The park rangers said that the cairns should only be built by trail workers for the purpose of navigation, safety, or showing where new or hard-to-follow trails are.
That means chances are if you see one, it was constructed by a hiker and should be dismantled.