If You Ever Come Across a Rock Cairn, Yosemite National Park Says to Knock It Over
People have used manmade rock stacks—also called rock cairns—since prehistoric times. These markers have served a myriad of purposes, but are usually placed to give directions to travelers and provide protection from the wind. However, while cairns have a long history, their function is currently being misused by many hikers and travelers. That is why Yosemite National Park reminds its visitors to knock over any rock stacks they see.