But, because these are nearly always made from the same materials as the surrounding landscape, they blend into the background -- giving them natural camouflage in your photos. The first picture of this cairn (left) was hard to see. The solution? Try moving your camera low to the ground and use the sky as background for more contrast, or experiment with other angles.

But don't take too long arranging your photo either -- get out there and enjoy your hike -- and have fun!