This July, The Rolling Stones will play London's Hyde Park for the first time in 44 years. The band's last concert there — July 5, 1969 — turned out to be a defining moment in musical history, which those who were there will never forget. Mick Jagger hasn't.

"It was kind of strange," Jagger recalls over the phone. "You know, it was a free concert. Brian Jones, who was a founding member of the band, had very recently died."

Jones had died just two days earlier. He was a brilliant musician, undone by drugs and alcohol. A few weeks prior, he and the Stones had parted company. Stones superstar Keith Richards says the band members felt they should go ahead with that concert, despite Jones' death.

"I mean all those people were coming," Richards says. "It was one of those showbiz things, really, wasn't it? The show must go on, you know."

Hyde Park was swamped as never before. A quarter of a million people gathered there, drenched by sunshine and marijuana smoke. Philip Norman, author of several books on the Stones including a new biography of Jagger, was in London that day.

"It actually was the high-water mark of the hippie sensibility, because it really was love and peace," Norman says. "There was a sense, yes, of an almost quasi-religious gathering in memory of Brian Jones, who still had a huge fan base. But it quickly turned into a showcase for Mick Jagger."

Jagger transfixed the crowd the moment he walked out.

"Mick was wearing this extraordinary white fluffy garment which looked like a little girl's party dress," Norman says. "It actually was a suit. It had really been made for Sammy Davis Jr., and Mick had borrowed it."