11 Most Endangered Historic Places

Nine Mile Canyon

Year Listed: 2004
Location: Utah
Threat: Development


Photo: National Trust for Historic Preservation


Located in a remote part of Utah, Nine Mile Canyon is often called "the world's longest art gallery," as it contains more than 10,000 images carved and painted onto canyon walls by Native Americans. It also is home to numerous archeological sites, including pit houses, granaries, and village locations.

At the time of its listing as one of America's Most Endangered Historic Places, the historic canyon faced increasing pressure from tourism, recreation, and energy development that threatened its significant prehistoric and historic resources. In particular, the truck traffic associated with natural gas development on the plateau above the canyon caused dust and potentially corrosive chemicals to settle on the canyon's rock art sites.