INDIO, UNITED STATES • The Desert Trip mega-festival of rock greats is meant to be historic and Paul McCartney on Saturday served as a willing instructor, presenting a musical journey from pre-Beatles fare to hip-hop collaboration.
Tearing through a three-dozen song set that enraptured a 75,000- strong crowd in the California desert, the former Beatle welcomed to the stage fellow rock elder Neil Young - the day's other performer - for a mash-up that built into the anthem Give Peace A Chance.
Desert Trip, forecast to be the most lucrative music festival in history, is bringing together six of the biggest names in rock over back-to-back weekends with identical line-ups.
The festival opened last Friday with The Rolling Stones who, in their signature blues rock style, played an unexpected cover of Come Together by The Beatles - the fellow British rock superstars often viewed as the Stones' rivals.
McCartney, 74, returned the favour by performing the early Stones' single I Wanna Be Your Man, written by McCartney and John Lennon.
He turned his set into a retrospective, reaching back to 1958's In Spite Of All The Danger, an early and often forgotten song by The Beatles' early incarnation, The Quarrymen.
McCartney - whose audience appeared younger than the Stones' baby-boomer-dominated crowd - then summoned his raspiest voice for FourFiveSeconds, his 2015 collaboration with rap and R&B mega- stars Kanye West and Rihanna.
He also paid tribute to his late bandmates Lennon and George Harrison. For Harrison, he played the songwriter's Something - on ukulele, with McCartney trying twice after finding the instrument out of tune. "At least it proves we're live, right?" he said.
He said he still heard nervousness in his own voice in the recording of The Beatles' first single, Love Me Do, and dedicated the song to producer George Martin, who died in March. "It was George who signed us to a record contract, so without him, there wouldn't be any Beatle recordings," McCartney said. "So we love him and we thank him."
He brought out a fireworks show and perilous-looking on-stage pyrotechnics for Live And Let Die, reinforcing the spirit of celebration at the festival.
Young, 70, playing his own set before McCartney, put on a more politically engaging show as the folk rocker pressed his environmental activism.
A banner on an Indian teepee set up on stage read "Water Is Life" - a pertinent message for a festival taking place in a parched but populous desert - and Young played before a backdrop of an oversized bag of seeds labelled as local and organic.
The staunch critic of genetic modification brought environmental questions symbolically to stage, with actors planting seeds and later dressed in protective gear as if cleaning chemical or nuclear waste.
Casting the aura of a folk-rock church service, he performed triple duty on organ, harmonica and vocals for Mother Earth (Natural Anthem) as he asks the planet in his powerful yet warbling voice, "How long can you give and not receive?"
But he showed that his appeal extends beyond political allies as he put on a musical tour de force, with marathon jamming alongside his band Promise Of The Real and hard-driving guitar solos on his signature hits, Down By The River and Rockin' In The Free World.
Young, who earlier denounced Mr Donald Trump for playing Rockin' In The Free World at campaign events, said that the scandal-plagued Republican candidate had a new campaign theme in Young's song Welfare Mothers, with its ironic refrain, "Welfare mothers make better lovers".
But Young quipped that Mr Trump may have another message from Sunday's headliner Roger Waters, the force behind Pink Floyd's The Wall (1979). Mr Trump, a staunch critic of immigration, has vowed to build his own wall on the Mexican border to "make America great again".
Young said of Waters: "Roger's gonna build a wall and we're gonna make Mexico great again."
On Sunday night, Pete Townshend, 71, and Roger Daltrey, 72, of The Who proved that age was no barrier to good rock 'n' roll. They got the baby boomers in the crowd reminiscing with classics such as Who Are You, The Kids Are Alright, My Generation, The Seeker and songs from their rock opera Tommy. They closed the night with hits Baba O'Riley and Won't Get Fooled Again.