[Updated at 5:42 p.m. ET] A Philadelphia gym where boxing great Joe Frazier trained and historic post offices nationwide are among the United States’ most endangered historic places, according to an annual list that a preservation group released Wednesday.

The 25th annual "America’s 11 Most Endangered Historic Places," released by the nonprofit National Trust for Historic Preservation, lists what the group says are examples of important buildings, districts or landscapes that are at risk of destruction or irreparable damage.

The list includes the converted three-story brick Philadelphia warehouse where Frazier, a two-time heavyweight champion who handed Muhammad Ali his first professional loss in 1971's "Fight of the Century," trained throughout his career, according to the Preservation Alliance for Greater Philadelphia.

Frazier kept the gym open after his 1976 retirement, but it closed in 2008, three years before his death at age 67, according to the alliance.

The building, now home to a furniture store and two vacant floors, is for sale. In putting the building on its list, the NTHP says it hopes to identify a preservation-minded buyer and raise $10,000 to cover the costs of nominating it to the Philadelphia Register of Historic Places and the National Register of Historic Places.

"Joe Frazier was a sports legend, and he deserves a place that celebrates his legacy and his contributions to the sport of boxing,” Stephanie Meeks, NTHP president, said in a news release. "Without question, Joe Frazier's Gym is an important historic and cultural site, and bringing both protection and recognition to this site by placing it on the local and national registers would be a fitting tribute to one of our greatest athletes of all time."

Also on the list are what the group calls historic post office buildings that are closed or that may close in the near future. The group says that developers who would like to purchase and rehabilitate the buildings sometimes abandon their pursuit because they don't get timely or clear answers from the U.S. Postal Service regarding their disposition.

"There needs to be a clear and consistent process with these buildings no matter how they are disposed of, and that has not been provided," Chris Morris, a NTHP senior field officer, said by phone Wednesday.

In an e-mail to CNN, Postal Service spokeswoman Sue Brennan wrote that the service wants "to sell the property we have on the market," and that it is working with real-estate service provider CBRE to do this.

"And we follow all of the established laws and provisions regarding historical properties," Brennan wrote.

About 500 post offices have closed in the last two years, according to CNNMoney. The Postal Service, which reported a $5.1 billion loss last year citing a down economy, declining mail volume and a congressional mandate to prefund retirement health care benefits, recently backed off a plan to close thousands more post offices, deciding instead to cut hours at 13,000 rural sites, CNNMoney reported.

The NTHP's lists have highlighted 242 places over the last 25 years, with sites rarely appearing on the list more than one year.

(See the 2011 list)

The lists have "been a powerful tool for raising awareness and rallying resources to save endangered sites from every region of the country," the group said in the release.

"At times, that attention has garnered public support to quickly rescue a treasured landmark; while in other instances, it has been the impetus of a long battle to save an important piece of our history," the group said.

The 2012 “America’s 11 Most Endangered Historic Places” list:

Gym where Joe Frazier trained, Philadelphia

Historic U.S. Post Office buildings

Bridges of Yosemite Valley, California

Ellis Island Hospital Complex, New York Harbor, New York and New Jersey

Last known surviving boyhood home of Malcom X, Boston

Princeton Battlefield, Princeton, New Jersey

Sweet Auburn Historic District, Atlanta

Terminal Island, Port of Los Angeles

Texas courthouses

Theodore Roosevelt’s Elkhorn Ranch, Billings County, North Dakota

Village of Zoar, Ohio

Do you know of a building, district, municipality or landscape that you think should be on this list? Please leave a comment below.