A Cairn Marks The Presence Of A Visitor Of The La Fortuna River In Costa Rica. Stock Photography

Cairns are used as trail markers in many parts of the world, in uplands, on moorland, on mountaintops, near waterways and on sea cliffs, as well as in barren deserts and tundra. They vary in size from small stone markers to entire artificial hills, and in complexity from loose conical rock piles to delicately balanced sculptures and elaborate feats of megalithic engineering. Cairns may be painted or otherwise decorated, whether for increased visibility or for religious reasons. The building of cairns for recreational purposes along trails, to mark one`s personal passage through the area, can result in an overabundance of rock piles. This distracts from cairns used as genuine navigational guides, and also conflicts with the Leave No Trace ethic.