Balanced Art World International festival in Ottawa, Canada, and the European Stone-Stacking Championships in Scotland. Opposition The number of rock piles created in this manner in natural areas has recently begun to worry conservationists because they can expose the soil to erosion and aesthetically intrude upon the natural landscape. Rock stacking in national parks has been called vandalism by the U.S. National Park Service and by the Queensland Parks and Wildlife Service. Historic England have said that stone piling near a scheduled monument would be illegal if judged to have been at risk of damaging the site, and on the Isle of Skye more than 100 locals organized to dismantle rock stacks left there by tourists. Some parks use deliberate arrangements of rocks as navigational guides to hikers, with the Gorham Mountain trail at Acadia National Park using markers of a flat rock on two "legs" with another rock on top pointing in the direction of the trail, for the benefit of those who have lost their way. Hobbyists stacking rocks in the wilderness risk confusing such messages. One draw of the outdoors is a perception of solitude, and many people see rock piles as an aesthetic intrusion on the landscape, and an unwelcome reminder that even in the wilderness, they're surrounded by the presence of other people. Leave No Trace recommends that rock balancers dismantle their piles and return the stones to their original locations when they're finished. "Disturbing or collecting natural features (plants, rocks, etc.) is prohibited" in U.S. national parks because these acts may harm the flora and fauna dependent on them. Destruction of wildlife and habitats Rock piling in streams silts the water, disrupts critical habitat, and can kill rare wildlife. In a river in Pisgah National Forest, scientists have repeatedly found protected Eastern hellbender salamanders crushed under the piles of rocks that tourists build midstream. In addition to the direct killing that takes place while the rocks are being moved, the flat cobbles that would make the best cover for hellbenders to live under tend to be the same individual rocks that rock pilers seek out to incorporate into balanced piles, chutes, and dams; this activity makes the best rocks unavailable to be used as habitat. Dismantling the piles and dispersing the stones does not seem to prevent their being repeatedly stacked into new piles. The biologists suspect that rock piling may be a widespread