Sponsored by the NYNJ Trail Conference, and The Stone Trust, in 3 days 20-30 of us learned how to build stone walls. With 4 instructors we built 150 running feet of ~4-foot high stone wall in front of the trail conference headquarters in Mahwah, NJ. Kind of like Tom Sawyer, but heavier and more expensive. Also, the work will not have to be re-done for 100 years. See the class.