images of many of the cliffs. Site access Cultural considerations Some areas that are popular for climbing, for example in the United States and Australia, are also sacred places for indigenous peoples. Many such indigenous people would prefer that climbers not climb these sacred places and have made this information well known to climbers. A well-known example is the rock formation that Americans have named Devils Tower National Monument. Native American cultural concerns also led to complete climbing closures at Cave Rock at Lake Tahoe, Monument Valley, Shiprock and Canyon de Chelly. Climbing activities can sometimes encroach on rock art sites created by various Native American cultures and early European explorers and settlers. The potential threat to these resources has led to climbing restrictions and closures in places like Hueco Tanks, Texas, and portions of City of Rocks National Reserve, Idaho. In Australia, the monolith Uluru (Ayers Rock) is sacred to local indigenous communities and climbing is banned on anything but the established ascent route (and even then climbing is discouraged, and soon to be discontinued). Elsewhere in Australia, many formerly popular climbing routes in areas such as the Grampians and Arapiles have been closed due to indigenous cultural concerns. Indigenous peoples are not the only cultures that object to climbing on certain rock formations. Professional climber Dean Potter kicked off a major controversy when he ignored long-accepted convention to scale Delicate Arch in 2006, resulting in strict new climbing regulation in Arches National Park. Private property Many significant rock outcrops exist on private land. Some people within the rock climbing community have been guilty of trespassing in many cases, often after land ownership transfers and previous access permission is withdrawn. In the U.S. the climbing community responded to access closures by forming the Access Fund. This is an "advocacy organization that keeps U.S. climbing areas open and conserves the climbing environment. Five core programs support the mission on national and local levels: public policy, stewardship and conservation (including grants), grassroots activism, climber education and land acquisition." In the U.K. the British Mountaineering Council represents climbers and their interest of public access to crags, cliffs and boulders. In Europe there are different rules in different countries regarding the rights of landowners and climbers. Environmental impact Although many climbers adhere to "minimal impact" and "leave no trace" practices, rock climbing is sometimes damaging to the environment. Common environmental damages include: soil