Washington ? Anyplace else, the scarred concrete steps would be an eyesore. At ground zero on Sept. 11, 2001, they were a last chance for escape. Now they stand as the last surviving above-ground piece of the World Trade Center.

The “Survivors Staircase” was named one of the nation’s most endangered historic places Wednesday, along with whole swaths of New Orleans and Mississippi damaged by Hurricane Katrina.

By singling out the staircase and sections of the South, the National Trust for Historic Preservation is seeking to preserve areas hit by the two biggest American disasters of recent memory. Katrina, noted trust President Richard Moe, “damaged more historic homes than any event in the history of the country.”

The trust is a private nonprofit group founded in 1949.

In New York, the rumbling of construction around ground zero has weakened the staircase, and it is not included in plans for a new tower.

To Sept. 11 survivor Patty Clark, the Trade Center staircase is “symbolic of all of us who were witnesses to that day. It’s still strong, somewhat damaged, but that’s kind of like we all are.”

The Vesey Street Staircase in New York City is the only surviving above-ground remnant of the original World Trade Center. The staircase is on a list of most endangered historical sites.

Clark and other employees of the Port Authority of New York and New Jersey used the staircase to escape Tower 1 after the terror attacks in New York.

She had already walked down 65 flights of stairs when she got to the World Trade Center plaza. Debris from Tower 2, which had just collapsed, filled the plaza, leaving the open-air staircase as the only way out. She and other employees followed the stairs down to ground level at Vesey Street and raced north, escaping just minutes before their own tower collapsed.

In the South, historic Mississippi towns and New Orleans neighborhoods face wholesale demolition after the 2005 hurricane. Moe said development pressures may lead towns and property owners to relax building codes and replace historic homes rather than repair them.

Also cited on the Trust’s new list of endangered historic places are the retirement home of Confederate President Jefferson Davis and Pascagoula’s La-Point-Krebs House.

Other sites on the most endangered list were:

¢ The Smithsonian Arts & Industries Building in Washington.

¢ Blair Mountain Battlefield in Logan County, W.Va.

¢ Doo Wop Motels in Wildwood, N.J.

¢ Fort Snelling Upper Post in Hennepin County, Minn.

¢ Kenilworth, Ill., an example of the intense development pressure to tear down early 20th century homes and replace them with what the group decries as hulking mansions.

¢ Kootenai Lodge in Bigfork, Mont.

¢ Mission San Miguel Arcangel in San Miguel, Calif.

¢ Over-the-Rhine Neighborhood in Cincinnati.