sentences: "In 2004, due to concerns about energy development and increasing recreational and tourist traffic, Ninemile Canyon was named on the National Trust for Historic Preservation's list of America's Most Endangered Places.In 2009, 63 sites in the canyon were added to the National Register of Historic Places, with another 164 added in 2012 and 101 in 2014, and the BLM has announced plans to nominate some 600 more in years to come.