Cairn

A cairn is a human-made stack or pile of rocks used as a trail marker or navigation aid in outdoor environments. These stone structures help hikers and backpackers stay on designated trails, especially in areas where the path may be unclear due to rocky terrain, snow cover, or sparse vegetation. Cairns are commonly found on mountain peaks, desert trails, and above treeline where traditional trail blazes are not practical, serving as crucial waypoints for safe navigation in the backcountry.