"People are still looking at Picasso, at artists who broke through the constraints of their time period to come up with something that was unique..." once said Robert Greenfield, associate editor of Rolling Stone magazine.
"In the form that they worked in - in the form of popular music - no one will ever be more revolutionary, more creative and more distinctive than The Beatles were."
Today, Greenfield's sentiments are still shared by many and, even in 1969, The Beatles' influence on popular culture was huge.
So, what a great surprise it must have been to lunchtime commuters when the Picassos of their time chose to play an impromptu gig on the roof of Apple Records, London.
Years had passed since the Fab Four had chosen to abandon live performance, after their tours became increasingly drowned-out by the screams of Beatlemania.
By the time a rock 'n' roll din erupted above the heads of unsuspecting Londoners, the group's music had expanded into unimagined territories, featuring weird electronic effects and 40-piece orchestras.
As they played that lunchtime, expressions in the gathered crowds - from the street, scaffolding and neighbouring windows - reportedly ranged from amused curiosity to disgust, as they gazed at Apple's roof.
Perhaps unsurprisingly - and in the spirit of the band's rabble rousing early days - the ragged performance was eventually cut-short by the police.
Of course, the Apple Records rooftop gig would turn out to be The Beatles' last-ever public performance.
Nevertheless, exactly 41 years on, the public's love of the Fab Four continues to this day.
John Lennon has become the fourth highest earning dead celebrity according to Forbes since his assassination in 1980. His estimated net worth currently stands at $24m, and is growing.
Needless to say, memorabilia sales have played a massive part in his estate's wealth.
In a December 2009, a special Christmas edition of the monthly Beatles Book - from the Mop Tops' heyday in 1963 - sold for a remarkable $12,000 at Bonhams.
Elsewhere, an artefact which may have contributed to The Beatle's decision to quit touring, a 1966 issue of the magazine Datebook featuring Lennon's infamous "We're more popular than Jesus now" quote, sold in New York.
The magazine, whose contents attracted death threats from some far-right Christian groups upon its release, sold to an orthopaedic surgeon for $12,713.
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