Philadelphia ? Live 8 will have to be pretty stupendous to equal its 1985 predecessor. Live Aid set a standard for ambition, scope, impact and musical talent that is unsurpassed 20 years later.

On a swampy July 13, 32 representatives of rock royalty performed in front of 100,000 sweating fans at Philadelphia’s JFK Stadium (with a similar number of acts onstage at Wembley Stadium outside London).

Tickets cost $35 for the show that began promptly at 9 a.m. with a secular invocation from Joan Baez. “This is your Woodstock,” she proclaimed, “and it’s long overdue.”

Tom Farley arrived early from West Chester, Pa., with his wife.

“We figured we were seeing the rock-and-roll Hall of Fame for about $1 a band,” he says by e-mail. “Before noon, we had already seen Black Sabbath, the Four Tops, Judas Priest, the Beach Boys and more – every band topping the last one. It was an amazing show.”

The 14-hour marathon, run with military precision by promoters Bill Graham and the Electric Factory, raised more than $70 million for famine relief in sub-Saharan Africa. The ABC broadcast, with Dick Clark as host, was syndicated to 107 stations, and the concert was carried on MTV, a coup for the still-struggling cable channel.

In all, 1.9 billion people in 150 countries saw the show, fulfilling organizer Bob Geldof’s vision of “a global jukebox.”

The concert had been planned for July 6, but Geldof – who had initially opposed Philadelphia as the U.S. site – postponed it a week, hoping it would give newlywed Bruce Springsteen a chance to participate. The Boss eventually declined.

But the show featured many reunions, including the Who, Black Sabbath, Led Zeppelin, and Crosby, Stills, Nash & Young. And Teddy Pendergrass joined Ashford & Simpson onstage in his first public appearance since his paralyzing car crash in 1982.

Phil Collins was the cynosure of the day for his trans-Atlantic feat of performing at both Wembley and JFK. But Madonna received plenty of attention, too, primarily because nude photos of her had been published in Playboy the previous week.

Many people in attendance say there was a special atmosphere in the stadium that day.

“The excitement was like nothing I had experienced,” e-mails Li Gilman, who borrowed her parents’ car to drive from New York with a friend. “People just came together. None of the usual pushing, shoving, rowdy concert behavior.”