The first ever Glastonbury Festival - then called Pilton Pop Festival - was vastly different to how it is today.
The first Glastonbury Festival was called 'Pilton Pop'
In 1970 the festival was just a couple of fields filled with 1,500 'naked hippies' dancing to acts including Al Stewart and Marc Bolan.
But now, several years and many mud-field years later, the festival has expanded to an area the size of Bath, attracting 185,000 people.
Festival organiser Michael Eavis says he feels like his "whole life" has been consumed by it.
"The whole thing is so satisfying, and it's just worked, hasn't it?
"With all the hazards of the '80s, I knew there was a fight on our hands then. There was the legal stuff with the council and the problems with the rather inaptly named "peace convoy"!
Bruce Springsteen, Blur and Neil Young headlined in 2009
"So we had about 10 or 12 years of that to contend with. It all came good in the end, though. And the history of all that is actually quite important to us, I think."
The 2009 festival saw Blur, Bruce Springsteen and Neil Young headline. Although the festival had a sombre atmosphere due to Michael Jackson's death, Eavis said he thought it was the "best ever".
And now the pressure is not only on to top it, but also to make the 40th anniversary extra special.
"People are very interested in this 40 year thing. Everywhere I go, people are asking about. The expectations are really high. So we have to deliver on that. We're trying to get the best headliners in the world."
Currently Michael, his daughter Emily, Nick Dewey and Martin Elbourne are busy contacting musicians to see who can headline next year.
"We've all got our own contacts within the industry, you see. So, the four of us are at it all the time."
Michael added that there is a 'slight difference of opinion' between himself and Emily with regards to the main headlining act.
"But then it's a question of whether they're available. All the others shows - the Readings and Vs - pay a lot more for their headliners than we do. So she and I have to agree on who we're going to stick our necks out for."
He said as there is to be a tribute concert for Michael Jackson on in London near when Glastonbury is happening, he hopes there will be a lot of artists around.
What Eavis has given away is that the non-music side of the festival is set to be the best ever.
"It's not all about the headlining bands, there's so much else going on, with everything from Trash City to the Theatre & Circus fields. And people love it.
"I'm trying to increase the budget for that stuff. The area organisers are all so keen. We've really got a brilliant crew. They're as dedicated as I am, really. That's what makes it work."
Despite rumours that he is planning on retiring, he said there's another 10 years' left in him - and then he'll see where it goes from there.
"I've got no interest in retirement. One day I'll have no choice, presumably, but while I can choose I've got no interest in retirement."
Find out more about the festival's history with our interactive timeline:
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