In recent years, the exposed concrete stadium has been lauded for its architectural originality and held up as a stellar example of midcentury Modernist design. Its 326-foot-long cantilevered concrete roof — the longest span at the time — is crenelated, folding horizontally and vertically, and calls to mind the ripples of the waves and the sails of Miami’s ever-present boats.

In 2009, soon after the effort to save it began, the National Trust for Historic Preservation placed the stadium on its list of the 11 most endangered historic places in the United States. That delivered a much-needed boost to the Friends of Miami Marine Stadium, founded by Mr. Candela; Don Worth, a preservationist; and Jorge Hernandez, an architecture professor at the University of Miami.

Gradually, donations have rolled in. Of the $30 million needed to refurbish the stadium, the nonprofit group, which used the High Line in New York City as its model, has raised $19 million, although the city wants it to firm up those pledges.

“This stadium is the only one of its kind in the whole world; it’s rare in that sense,” said Stephanie K. Meeks, president and chief executive officer of the National Trust for Historic Preservation, which has helped raise funds for the stadium’s refurbishment. She said similar midcentury modern structures were being lost at an “alarming” rate across the country.

In 2010, the World Monuments Fund placed Miami Marine Stadium on its list of sites threatened by neglect or overdevelopment, alongside Machu Picchu and the Old City of Jerusalem. And in September, the Friends group received $180,000 from the Getty Foundation under a new program to help study how concrete ages and to see how best to remove the graffiti from the stadium and make the appropriate repairs. Other grant recipients this year include the Sydney Opera House and Frank Lloyd Wright’s Robie House at the University of Chicago.