Steve and I went to Ashland for fall photography back in 2011, and while we were walking around, we found these piles of rocks. At the time we didn't know what they were called, but we loved taking pictures of them!

I found some very nice information about stacking stones on this page, Garden and Bliss:

"Rock stacking has carried spiritual meaning across cultures for centuries. The act of balancing stones carries with it a practice of patience and a physical effort of creating balance. I love the idea of tangible prayer and finding new ways to express gratitude in my life. Each rock can signify an intention of grace for thankfulness, or offered up for another in need. Connecting nature in this externalized expression is uplifting and very powerful tool for expanding the spirit. A little silicone glue can help make smaller stone towers last through the seasons if used as a garden decoration or given as a gift."