The Boyd's inclusion on the list proved crucial in getting it on Philadelphia's historic register and staving off demolition, although it has yet to be redeveloped.
The trust hopes this year's citation could do the same for Frazier's gym, which is opposite Amtrak's renovated North Philadelphia station. Besides a gas station, the gym is the sole remaining structure on the block, which sits hard by the railroad viaduct.
The gym was not chosen for its architectural merit, said John Gallery, who heads Philadelphia's Preservation Alliance, but because of the role it played in African American and sports history. Frazier was a larger-than-life presence in Philadelphia who went on to mentor generations of young fighters at his gym.
"We'd like to see the building preserved because it embodies the qualities of the man," Gallery said.
Born in South Carolina, Frazier was the 12th child of a sharecropping family. He taught himself to box by spending hours punching a sack filled with bricks and dirt. "He's proof that ordinary people can achieve extraordinary things," said the National Trust's Brent Leggs, who was in Philadelphia on Wednesday to talk about the gym.
Frazier, who died last year at 67, was a dominant force in boxing for years, from the time he won an Olympic gold medal in 1964 until his retirement after his defeat by George Foreman in 1976. His long-standing rivalry with Ali also reflected the turbulent civil rights debates of the '60's and '70s. In an effort to prove his superiority over Ali, Frazier trained relentlessly in his gym's first-floor ring, and defeated him in the "Fight of the Century" at New York's Madison Square Garden in 1971.
The gym always has been something of a landmark because of its isolation at the prominent intersection at Glenwood Avenue. The building, thought to have been built between 1888 and 1895, was acquired in 1966 by a syndicate of Philadelphia leaders interested in supporting Frazier's boxing career after he won the Olympic medal. He paid them back with his winnings.
The gym's precarious condition came to the attention of the National Trust after a group of Temple University students was assigned to prepare mock nominations of endangered buildings by instructor Dennis Playdon.
The students, led by Ann Dinh and Michael Baker, became so interested in the history of Frazier's gym that they turned the assignment into a real project. After the students submitted their research to the Preservation Alliance, the organization put the building on its own endangered list in December. Preservationists said Wednesday the building could easily be renovated as a full-service gym.
Its inclusion on the endangered list is part of an effort to include places whose history resonates with a variety of ethnic and racial groups. In the past, buildings that played a crucial role in African American life often were overlooked because of their modest origins. In addition to Frazier's gym, the National Trust this year listed two important African American sites: Atlanta's Sweet Auburn Historic District, a once-segregated neighborhood that was the birthplace of the Rev. Dr. Martin Luther King Jr., and Malcolm X's boyhood home in Boston.
The list also serves as a way of flagging future threats to the nation's architectural heritage. Because of the financial troubles facing the U.S. Postal Service, the trust concluded that all historic post offices are endangered and included them as a group on this year's list.
Contact architecture critic Inga Saffron at 215-854-2213, firstname.lastname@example.org, or follow @ingasaffron on Twitter.