The National Trust for Historic Preservation's 2016 list of America's 11 most endangered places includes an iconic Arizona street.

The Sunshine Mile, a 2-mile stretch of Broadway Boulevard in Tucson, is cited on the list as one of Arizona's most significant concentrations of Midcentury Modern architecture. Most of the buildings there were constructed between 1939 and 1972.

The trust, which is dedicated to protecting significant places that represent America's culture and history, notes that the Sunshine Mile is currently threatened by a proposal to widen Broadway from four to six lanes, and up to nine lanes in some areas. Doing so would require the demolition of many of the street's iconic structures, but a coalition of Tucsonans is working to preserve them.

"The Sunshine Mile remains an important and irreplaceable part of Tucson’s history, and underscores recent research by the National Trust’s Preservation Green Lab, which indicates that the Sunshine Mile and other areas with historic, smaller buildings and mixed-vintage blocks contribute significantly to the city’s economic vitality, neighborhood livability and residential density," the trust says. "At a time when cities across the country are reusing their older buildings to attract residents and grow their local economies, the Sunshine Mile deserves to be an integral part of the city’s future."

Last year's list also included Arizona locations: the Grand Canyon, which we feature just about every month in Arizona Highways, and Oak Flat, which we featured in our June 2016 issue.

Other locations on this year's list include Bears Ears, on the Colorado Plateau in Utah and the San Francisco Embarcadero. To see the full list, click here.

Credit for all photos: GM Vargas Photography: Jude Ignacio and Garardine Vargas.