The National Trust for Historic Preservation is identifying 11 places around the U.S. that it says are at risk because of development or neglect.
The National Trust list, released Tuesday, includes Route 66, African-American historic sites in Connecticut and Mississippi, and Denver's Larimer Square.
Route 66 which is often called America's Main Street stretches across eight states, including Oklahoma. About 45,000 people travel along Route 66 through Oklahoma each year, and 30 percent of them are from other countries.
6/8/2018 Related Story: Thousands Hit Oklahoma's Route 66 For Adventure
The National Trust for Historic Preservation is a private nonprofit. Its annual endangered places list can mobilize support for preservation.
The Associated Press contributed to this report.