What is a pile of rocks that works as a trail marker called?

Hikers often use cairns, or a pile of rocks, to mark their trail if they go off the beaten path. Cairns can also be left for other hikers to use.

When making a cairn, it should be positioned in a flat, open area to increase its visibility. Use rocks that are in contrast to the trees and terrain around it. For instance, light-colored rocks will be quite distinct against a backdrop of pine trees.

Several sizes and types of rocks should be used for constructing the cairn. Large, flat rocks work best for the base while smaller and rounder rocks can be used as you build it upwards. A strong base will allow the construction of a taller cairn. Before walking away, check for any wobbles or deficiencies in the structure to ensure it doesn't fall to the ground.