And that's all from me. I hope you've enjoyed our live coverage of a truly historic day for Runnymede.
Read more about Magna Carta's 800th anniversary here.
All smiles
Getty ImagesCopyright: Getty Images
Smiles from the Queen during celebrations to mark the anniversary of one of the most significant documents in British history.
Inspired by art
Getty ImagesCopyright: Getty Images
Here's Prince William examining the 12 chairs that were created by Hew Locke.
The Jurors
One of the highlights of today's ceremony was the unveiling of Hew Locke's new artwork on the meadow called The Jurors.
He said it was obvious he should work with the most important remaining part of Magna Carta - the right to trial by jury.
Spectacular flypast
PACopyright: PA
Here's a view of the Red Arrows over the memorial - exactly eight centuries after the ground-breaking accord.
On parade
Getty ImagesCopyright: Getty Images
A moment from the ceremony earlier - soldiers standing on parade at the Magna Carta Memorial.
Clause 39
Here's the part of Magna Carta that inspired Hew Locke's artwork - and what we know as habeas corpus.
BBCCopyright: BBC
It sets out the principles of lawful arrest and detention.
More on Magna Carta 'freedom'
A few more answers have come in to our question - what does freedom mean to you? Here's one from John Leibee.
He writes: "Freedom is the opportunity to do what is good and just. Hello from America!"
What Magna Carta shows us
One more observation from Dr David Starkey on Magna Carta's significance.
BBCCopyright: BBC
He says: "What Magna Carta teaches us essentially is that all politics is about clash.
"It's about rival interests. It's about rival opinions. It's about rival values. And finally, everything has to be some sort of compromise."
King, bishop or baron?
As part of the 800th anniversary celebrations, Royal Holloway University created a quiz where you can find out what part you might have played in the drama in Runnymede in 1215.
Getty ImagesCopyright: Getty Images
Have a go and find out whether you are a king, a bishop or a baron.
Court eviction hearing
We've got a short update on the eco-villagers - the community facing eviction on Coopers Hill.
Daniella Zalcman Copyright: Daniella Zalcman
Their hearing started earlier and will resume after lunch, says defence lawyer Peter Phoenix.
"It's an interesting, exciting and iconic case," he adds. "We're going to be arguing our rights under Magna Carta and the Forest Charter and under common law."
The hearing resumes at Guildford County Court in a few minutes.
Discover why the Americans think Magna Carta is so awesome and discover how much political power is in your pocket.
What is Magna Carta again?
Mark Aldrich tweets: "#MagnaCarta is 800yrs old today. Does anyone know what it is?
"Imagine someone in #USA not knowing the #BillOfRights !"
'Nothing less than dignity'
"The principles traced back to Magna Carta represented a concept that is nothing less than the dignity of man," said US Attorney General Loretta Lynch a short while ago.
"Those fundamental age-old principles have given hope to those who face oppression.
ReutersCopyright: Reuters
US Attorney General Loretta Lynch joined the celebrationsImage caption: US Attorney General Loretta Lynch joined the celebrations
"They have given a voice to those yearning for the redress of wrongs."
Commemorative plaque
Adrian Harms
BBC Surrey
And here's the plaque the Queen unveiled earlier.
BBCCopyright: BBC
She was joined by the Duke of Edinburgh and Prince William at Runnymede.
'Long, difficult march'
A few thoughts from US Attorney General Loretta Lynch who spoke earlier at the ceremony.
She says Magna Carta's adoption served as a signpost on a "long and difficult march".
"Those who forged its compromise stood as early travellers on the road to justice."
'Foundation of our country'
American Bar Association president William Hubbard told BBC Surrey the Magna Carta Memorial was erected in 1957 with the help of donations from 9,000 US lawyers.
BBCCopyright: BBC
Mr Hubbard, who comes from South Carolina, said the document "absolutely is the foundation of our country".
"Magna Carta's principles were embedded in the state constitutions of the colonies, and later in the US constitution."
Royal barge
The royal barge Gloriana has been on the Thames at Runnymede.
BBCCopyright: BBC
It led a flotilla of about 200 boats on a voyage from Berkshire to Surrey.
Queen statue
Magna Carta celebrations have taken place all weekend.
About £1m has been spent on the 800th anniversary by Conservative-run Surrey County Council, including the co-commissioning of Hew Locke's artwork.
The local authority believes this will boost the local economy and the profile of the area, both nationally and internationally.
Plans are being developed to improve visitor facilities in Runnymede - but that is proving controversial, with opposition councillors questioning spending priorities, particularly when services are being cut.
The next 800 years
The Magna Carta 800th committee was behind many of the anniversary celebrations around the country.
British LibraryCopyright: British Library
They tweeted: "The @ABAesq #MagnaCarta Memorial has been rededicated. Here's to another 800 years of #Liberty!"
'Kissing babies'
John Cooper QC tweets: "Politicians quoting Magna Carta is the equivalent of them kissing the baby during an election. #MagnaCarta"
Red Arrows video
Adrian Harms
BBC Surrey
See a video of the Red Arrows flypast which took place at 12:15 - marking the fact Magna Carta was sealed in Runnymede in 1215.
BBCCopyright: BBC
And then they were gone...
Revolutionary document
Earlier, David Cameron talked about the revolutionary impact of Magna Carta "altering forever the balance of power between the governed and the government".
AFPCopyright: AFP
He said down the years it had inspired fighters in the English Civil War, the Chartists, the Suffragettes, the founders of the first American states, Gandhi, Nelson Mandela and "anyone challenging injustice or checking arbitrary power".
Explaining 'Runnymede'
Tanya Gupta
BBC News
In the lead-up to the celebrations, I went down to Runnymede meadow to try and find out why people were so surprised the site was still just a field.
BBCCopyright: BBC
At the memorial though, people seemed even more taken aback that the structure had been put up by the American Bar Association.
Here's our first reply to the question - what does freedom mean to you?
Satch Norton says it is "the right to choose" whether or not to have fracking, fluoride in drinking water, industries that supply weapons to repressive regimes, British soldiers fighting in other countries, and the right to choose who sits in the House of Lords.
We want to hear what you think. Tweet @BBCSurrey or email us.
'Talk about justice'
Hew Locke's artwork, The Jurors, featuring 12 chairs arranged in a square, was unveiled at Runnymede earlier.
"They are dare I say it, beautiful, complex, multi-layered, he says."It's a place for people to sit down and talk about ideas of justice," he said.
He wants people to go up to the chairs and explore the work. "It only works if you go and sit on them."
Wonderful landscape
Geri Silverstone, from the National Trust, said Runnymede was a fantastic place and a wonderful landscape with views of Windsor Castle to Heathrow Terminal 5 from Coopers Hill.
BBCCopyright: BBC
"You've got old and new, you've got a river. It's a fantastic bit of Surrey that we're very proud to be associated with."
He said work to improve the site as a tourist destination was planned to continue beyond the 800th anniversary.
Time for lunch
Adrian Harms
BBC Surrey
The formalities are over and its time for the picnics.
BBCCopyright: BBC
And the sun has come out for the celebrations too.
Flypast expected
The Red Arrows are helping to mark the 800th anniversary with a series of flypasts.
They will be over Runnymede at 1215 BST and Lincoln Castle at 1503 BST.
Getty ImagesCopyright: Getty Images
According to Visit Lincoln, the city is the only place in the world where you can find an original copy of Magna Carta together with the Charter of the Forest.
Votes for women
Children at the event are getting interested in the suffragette movement and its links with Magna Carta.
BBCCopyright: BBC
Here are some pupils from the Hythe School with an effigy of Emmeline Pankhurst.
Women's rights
The charter has inspired political movements over the centuries - not least the suffragettes.
Research by Alexander Lock on the British Library website found that in 1915, suffragette Helena Normanton argued the disenfranchisement of women contravened Magna Carta clauses 39 and 40.
BBCCopyright: BBC
And there's more on women's rights - Magna Carta clause 8 dealt with the rights of widows.
Puppet show
Adrian Harms
BBC Surrey
The Magna Carta 800 anniversary events continue at Runnymede.
BBCCopyright: BBC
I found these guys listening intently to the speeches a short while ago.
Freedom - what it means to you
Magna Carta famously dealt with the liberties of free men - and so we're asking what freedom means to you.
BBCCopyright: BBC
Tweet us @BBCSurrey or email us your comments. We'd love to know what you think.
'Magna Carta squatters'
Unofficial Magna Carta celebrations are also taking place today on Coopers Hill - by the inhabitants of Runnymede Eco-Village.
They are known as the Magna Carta squatters because of their proximity to the memorial.
They are facing eviction by landowners Orchid Runnymede - their hearing takes place at Guildford County Court later. We'll be bringing you the outcome here.
Magna Carta legacy
Professor Justin Fisher from Brunel University has put together an exhibition at Runnymede looking at the influence of Magna Carta.
He says the document inspired the Bill of Rights of 1689 in Britain, the Declaration of the Rights of Man and the Citizen of 1789 in France, and the Bill of Rights in the US in 1791.
PACopyright: PA
He was in the second row for today's celebrations. Earlier, he tweeted that he would be presented to the royal party afterwards.
US dignitaries
An update on the Magna Carta celebrations from Get Surrey.
Get SurreyCopyright: Get Surrey
Eleanor Surrey Ad tweets: "The U.S. Attorney General is speaking at the memorial. I am proud, I am honoured and I am humbled."
David Cameron called for fundamental reforms to UK human rights laws to "safeguard the legacy" of Magna Carta at today's ceremony.
He said the principle of Magna Carta was "as relevant today as it was then" but the notion of human rights in Britain had been "distorted and devalued".
The Conservative government wants to scrap the Human Rights Act and assert the supremacy of the UK's supreme court over the European Court of Justice in Strasbourg.
More hilarity
Karen Shakespeare has come up with another Magna Carta joke.
She tweeted: "Where did King John sign the #MagnaCarta? At the bottom. #crackerjoke"
Twitter has seen a deluge of Magna Carta comments during the ceremony. Some have been light hearted and others more serious.
The Queen has left the ceremony at Runnymede. The royal car was surrounded by crowds of people as it drove from the meadow.
BBCCopyright: BBC
Earlier, Her Majesty met people attending the celebrations. Thousands of people were there and a few lucky guests had the chance to meet her.
Rededication ceremony
Ben Cowell from the National Trust has tweeted a picture of the Magna Carta Memorial rededication.
National TrustCopyright: National Trust
The trust owns the Runnymede site which has been dubbed the "birthplace of modern democracy".
BBC iWonder: Power in your pocket
Living in Britain today, it's hard to imagine a time when nearly all of us had no say in how the country was run, or how our rulers governed us. That time was 800 years ago.
Before then, kings could do pretty much whatever they wanted. And they did.
But in the year 1215 their authority was challenged. The resulting agreement was called Magna Carta and changed the relationship between ruler and ruled forever.
BBC iWonder looks at the power of the technology you can fit into your pocket.
Same spot 800 years later
The Queen and the Duke of Edinburgh were joined by the Archbishop of Canterbury Justin Welby and Prime Minister David Cameron at Runnymede earlier.
PACopyright: PA
It all happened on the same spot where King John accepted the historic document that limited the power of the Crown in 1215.
Marking 800 years
One of the high profile moments from today's ceremony was David Cameron's speech.
PACopyright: PA
He talked about British pride in Magna Carta and how its principles are held dear by many.
Many happy returns
Nicholas Davies has tweeted: "So thankful to be living in a country where the Government is not above the law.
"Many happy returns #MagnaCarta"
Queen unveils plaque
The audience are on their feet as the Queen walks across the stage to unveil a plaque.
She is now meeting people who are at the ceremony today.
We'll bring you pictures of the Queen as soon as we get them.
Principles 'shine brightly'
David Cameron says Magna Carta is something every person in Britain should be proud of.
BBCCopyright: BBC
He says its principles shine as brightly as ever.
"We hold these things dear and we should hold them even dearer for the fact they took shape here on the banks of the Thames."
You can also see a short video of part of his speech here.
Magna Carta 'relevant today'
Prime Minister David Cameron is speaking at the celebrations.
"What happened in these meadows 800 years ago is as relevant today as it was then.
"All over the world people are still struggling to live by the rule of law."
Memorial flags
The Union flag is displayed alongside the US stars and stripes on the memorial today.
PACopyright: PA
Magna Carta has huge significance to a lot of Americans. Find out why here.
Speeches begin
Mark Carter
BBC Surrey
A hush has fallen over the meadow ahead of speeches by the Master of the Rolls and Prime Minister David Cameron.
More than 4,000 people have gathered in Runnymede for today's ceremony.
Queen follows King John route
David Starkey is at the event. "It's the kind of thing we Brits do so well," he says. "The whole thing is saying something important did happen and it's worth commemorating it."
He said the Queen, who had just arrived at Runnymede, had followed the expect route from Windsor taken by King John in 1215.
BBCCopyright: BBC
"I hope the Queen is in a better temper than King John would have been here 800 years ago. King John comes here dragged, furious, reluctant."
Google doodle
Today's Google doodle is an animation about Magna Carta.
GoogleCopyright: Google
It shows a line-up of barons with King John putting his stamp on Magna Carta after the deal is struck.
Art criticised
Hew Locke's new artwork is not to everyone's liking.
Alistair Pike has tweeted: "Putting out 12 chairs without a table isn't a #sculpture #MagnaCarta #BBCNews #art #chairs"
But tell us what you think. You can tweet us @BBCSurrey or email us.
Parade of flags
Adrian Harms
BBC Surrey
Events are taking place all over the meadow.
BBCCopyright: BBC
Here's a parade of flags by school children from Surrey - you can also see the video here.
Artwork unveiled
Adrian Harms
BBC Surrey
The Duke of Cambridge has unveiled The Jurors art installation at Runnymede.
We are are not the only ones covering the events in Runnymede.
BBCCopyright: BBC
Get Surrey is providing live updates from the ceremony and performances too.
Empty chairs in use
Hew Locke's art installation has now been officially unveiled.
BBC Surrey presenter James Cannon caught up with the the artist a short while ago.
BBCCopyright: BBC
The chairs include a representation of the key to Nelson Mandela's jail cell door.
Prince arrives
Adrian Harms
BBC Surrey
Prince William has arrived - with a crew of photographers behind him.
BBCCopyright: BBC
For the royal party, The Duke of Edinburgh, the Duke of Cambridge, Princess Anne and her husband Vice Admiral Sir Tim Laurence will be at the event.
Children performing
Jack Fiehn
BBC Surrey Political Reporter
Children are performing something called the Freedom Game on the meadow.
BBCCopyright: BBC
It's based on Magna Carta themes of human rights.
Orchestra performing
Adrian Harms
BBC Surrey
The London Philharmonic Orchestra is now performing at Runnymede.
BBCCopyright: BBC
And there's not a spare seat in the house.
Land activists
Phil Coomes
Picture editor
Back to the Runnymede eco-village where photographer Daniella Zalcman stumbled upon the group in February this year, and, after a few phone calls, began to visit every week or so.
Daniella Zalcman Copyright: Daniella Zalcman
Here's a photo she took of a sign on the fence that surrounds the community.
Tony Hancock
"Does Magna Carta mean nothing to you? Did she die in vain?" asked an exasperated Tony Hancock playing the jury foreman in an episode of his famous Half Hour.
BBCCopyright: BBC
BBC legal correspondent Clive Coleman writes: "Clearly not. Far from dying, Magna Carta has had a life longer, fuller and more influential than the most optimistic medieval baron could have imagined."
Expensive ice cream?
Lots of Magna Carta jokes on twitter. For a light-hearted approach see these tweets.
Tony Munky wrote: "Can't believe it has been 800 years since the Magna Carta was signed - only feels like yesterday! #magnacarta"
Getty ImagesCopyright: Getty Images
And lots of jokes about ice cream. One here from Pongo The Penguin: "@mrchrisaddison Magna Carta? I thought that was an expensive ice cream with raspberry in it"
Cathedral light bulbs
It's not just Runnymede that is marking 800 years of Magna Carta though, events are taking place all over the country.
Take a look at this light installation at Salisbury Cathedral.
Getty ImagesCopyright: Getty Images
It has about 6,000 colour-changing light bulbs suspended from the ceiling to celebrate the 800th anniversary.
Plaque unveiling
Today's event will include speeches by the Archbishop of Canterbury Justin Welby and Lord Dyson, Master of the Rolls.
BBCCopyright: BBC
And the Queen will unveil a plaque at the memorial to mark the occasion.
Listen live
BBC Surrey is at Runnymede meadow and broadcasting live throughout the morning. Listen here.
Road and river closures
The river is closed for today's ceremony - not just the roads.
BBCCopyright: BBC
The A308 Windsor Road which runs alongside the meadow will remain shut until late afternoon, as will the section of the River Thames that runs through Runnymede.
In the run up to the anniversary celebrations, BBC Surrey asked a few people around the county if they knew what Magna Carta was.
One woman said: "Didn't that happen in 1066 in Hastings?" Another said: "Wasn't it the Domesday Book?"
Someone speculated that it might have been a document signed somewhere between 1400 and 1600. If you're stuck, look at BBC iWonder.
'Magnificent irony'
Briony McDonagh has tweeted: "Runnymede Eco Village residents in court over eviction proceedings on the day of the #MagnaCarta celebrations in the field next door"
And she posted: "Someone, somewhere has a magnificent sense of historical irony #MagnaCarta #MagnaCarta800 #freetheland"
That hearing begins at 10:30 BST. We might find out the outcome while the ceremony is under way.
Visiting dignitaries
We're waiting for the national Magna Carta Foundation of Liberty ceremony to get under way at 09:00 BST.
BBCCopyright: BBC
Invited guests include members of the Royal Family and dignitaries from the UK and around the world.
More than 4,000 people are gathering on the normally tranquil meadow.
Foundation of US democracy
William Hubbard, president of the American Bar Association which put up the Magna Carta memorial in 1957, is at the celebrations. He said: "We could not be more excited. We are thrilled."
He said about 900 ABA members had come over to the UK to celebrate Magna Carta.
"It's the foundation of American democracy. It's absolutely the foundation of our country."
'Beautiful, intricate design'
National Trust director Dame Helen Ghosh loves how the chairs represent all eras and all continents in terms of liberty and the rule of law.
She says: "They're so intricate. The amount of time you could spend just gazing at the design is wonderful."
Artwork unveiled
And here's the first view of Hew Locke's artwork - inspired by Magna Carta's principles of justice.
Tom MorganCopyright: Tom Morgan
It shows 12 chairs arranged in a square - and it's called The Jurors.
Have you read it?
Sister Catherine Wybourne has tweeted: "I hope all those writing about Magna Carta today have actually read it.
"Sometimes one gets the impression some haven't. #MagnaCarta"
British LibraryCopyright: British Library
If you're not in a position to read the original medieval Latin on parchment, there are some handy translations around.
Here's one from the British Library, but remember it was amended and edited over the years.
Preparations on meadow
Jack Fiehn
BBC Surrey Political Reporter
All around me preparations are taking place for the main event in a few hours time.
There are tents all around the field and a huge stage with seats in front of it.
That's where the Queen and other members of the Royal Family will be later on this morning for speeches and music.
'So it begins'
The National Trust has tweeted a picture of the first guests arriving - under overcast skies although the weather is expected to brighten later.
National TrustCopyright: National Trust
The organisation wrote: "And so it begins... #MagnaCarta800"
Good morning
Tanya Gupta
BBC News
Welcome to our live page marking the 800th anniversary of the Magna Carta.
I'll be bringing you all the latest from the ceremony at Runnymede, where thousands of people including the Queen are gathering to mark the event.
You can tweet us @BBCSurrey and email us your pictures and comments.
Live Reporting
Tanya Gupta and Clark Ainsworth
All times stated are UK
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Latest PostThank you and that's it
Tanya Gupta
BBC News
And that's all from me. I hope you've enjoyed our live coverage of a truly historic day for Runnymede.
Read more about Magna Carta's 800th anniversary here.
All smiles
Smiles from the Queen during celebrations to mark the anniversary of one of the most significant documents in British history.
Inspired by art
Here's Prince William examining the 12 chairs that were created by Hew Locke.
The Jurors
One of the highlights of today's ceremony was the unveiling of Hew Locke's new artwork on the meadow called The Jurors.
He said it was obvious he should work with the most important remaining part of Magna Carta - the right to trial by jury.
Spectacular flypast
Here's a view of the Red Arrows over the memorial - exactly eight centuries after the ground-breaking accord.
On parade
A moment from the ceremony earlier - soldiers standing on parade at the Magna Carta Memorial.
Clause 39
Here's the part of Magna Carta that inspired Hew Locke's artwork - and what we know as habeas corpus.
It sets out the principles of lawful arrest and detention.
More on Magna Carta 'freedom'
A few more answers have come in to our question - what does freedom mean to you? Here's one from John Leibee.
He writes: "Freedom is the opportunity to do what is good and just. Hello from America!"
What Magna Carta shows us
One more observation from Dr David Starkey on Magna Carta's significance.
He says: "What Magna Carta teaches us essentially is that all politics is about clash.
"It's about rival interests. It's about rival opinions. It's about rival values. And finally, everything has to be some sort of compromise."
King, bishop or baron?
As part of the 800th anniversary celebrations, Royal Holloway University created a quiz where you can find out what part you might have played in the drama in Runnymede in 1215.
Have a go and find out whether you are a king, a bishop or a baron.
Court eviction hearing
We've got a short update on the eco-villagers - the community facing eviction on Coopers Hill.
Their hearing started earlier and will resume after lunch, says defence lawyer Peter Phoenix.
"It's an interesting, exciting and iconic case," he adds. "We're going to be arguing our rights under Magna Carta and the Forest Charter and under common law."
The hearing resumes at Guildford County Court in a few minutes.
Discover more
There's much more on Magna Carta on BBCiWonder.
Have a look at our Taking Liberties page and find out how the 1215 Magna Carta peace treaty shaped the freedoms of 2015.
Discover why the Americans think Magna Carta is so awesome and discover how much political power is in your pocket.
What is Magna Carta again?
Mark Aldrich tweets: "#MagnaCarta is 800yrs old today. Does anyone know what it is?
"Imagine someone in #USA not knowing the #BillOfRights !"
'Nothing less than dignity'
"The principles traced back to Magna Carta represented a concept that is nothing less than the dignity of man," said US Attorney General Loretta Lynch a short while ago.
"Those fundamental age-old principles have given hope to those who face oppression.
"They have given a voice to those yearning for the redress of wrongs."
Commemorative plaque
Adrian Harms
BBC Surrey
And here's the plaque the Queen unveiled earlier.
She was joined by the Duke of Edinburgh and Prince William at Runnymede.
'Long, difficult march'
A few thoughts from US Attorney General Loretta Lynch who spoke earlier at the ceremony.
She says Magna Carta's adoption served as a signpost on a "long and difficult march".
"Those who forged its compromise stood as early travellers on the road to justice."
'Foundation of our country'
American Bar Association president William Hubbard told BBC Surrey the Magna Carta Memorial was erected in 1957 with the help of donations from 9,000 US lawyers.
Mr Hubbard, who comes from South Carolina, said the document "absolutely is the foundation of our country".
"Magna Carta's principles were embedded in the state constitutions of the colonies, and later in the US constitution."
Royal barge
The royal barge Gloriana has been on the Thames at Runnymede.
It led a flotilla of about 200 boats on a voyage from Berkshire to Surrey.
Queen statue
Magna Carta celebrations have taken place all weekend.
A statue of the Queen, created by sculptor James Butler, was unveiled at Runnymede Pleasure Grounds on Sunday.
Spending controversy
Jack Fiehn
BBC Surrey Political Reporter
About £1m has been spent on the 800th anniversary by Conservative-run Surrey County Council, including the co-commissioning of Hew Locke's artwork.
The local authority believes this will boost the local economy and the profile of the area, both nationally and internationally.
Plans are being developed to improve visitor facilities in Runnymede - but that is proving controversial, with opposition councillors questioning spending priorities, particularly when services are being cut.
The next 800 years
The Magna Carta 800th committee was behind many of the anniversary celebrations around the country.
They tweeted: "The @ABAesq #MagnaCarta Memorial has been rededicated. Here's to another 800 years of #Liberty!"
'Kissing babies'
John Cooper QC tweets: "Politicians quoting Magna Carta is the equivalent of them kissing the baby during an election. #MagnaCarta"
Red Arrows video
Adrian Harms
BBC Surrey
See a video of the Red Arrows flypast which took place at 12:15 - marking the fact Magna Carta was sealed in Runnymede in 1215.
And then they were gone...
Revolutionary document
Earlier, David Cameron talked about the revolutionary impact of Magna Carta "altering forever the balance of power between the governed and the government".
He said down the years it had inspired fighters in the English Civil War, the Chartists, the Suffragettes, the founders of the first American states, Gandhi, Nelson Mandela and "anyone challenging injustice or checking arbitrary power".
Explaining 'Runnymede'
Tanya Gupta
BBC News
In the lead-up to the celebrations, I went down to Runnymede meadow to try and find out why people were so surprised the site was still just a field.
At the memorial though, people seemed even more taken aback that the structure had been put up by the American Bar Association.
I've tried to provide a few insights.
Freedom question
Here's our first reply to the question - what does freedom mean to you?
Satch Norton says it is "the right to choose" whether or not to have fracking, fluoride in drinking water, industries that supply weapons to repressive regimes, British soldiers fighting in other countries, and the right to choose who sits in the House of Lords.
We want to hear what you think. Tweet @BBCSurrey or email us.
'Talk about justice'
Hew Locke's artwork, The Jurors, featuring 12 chairs arranged in a square, was unveiled at Runnymede earlier.
"They are dare I say it, beautiful, complex, multi-layered, he says."It's a place for people to sit down and talk about ideas of justice," he said.
He wants people to go up to the chairs and explore the work. "It only works if you go and sit on them."
Wonderful landscape
Geri Silverstone, from the National Trust, said Runnymede was a fantastic place and a wonderful landscape with views of Windsor Castle to Heathrow Terminal 5 from Coopers Hill.
"You've got old and new, you've got a river. It's a fantastic bit of Surrey that we're very proud to be associated with."
He said work to improve the site as a tourist destination was planned to continue beyond the 800th anniversary.
Time for lunch
Adrian Harms
BBC Surrey
The formalities are over and its time for the picnics.
And the sun has come out for the celebrations too.
Flypast expected
The Red Arrows are helping to mark the 800th anniversary with a series of flypasts.
They will be over Runnymede at 1215 BST and Lincoln Castle at 1503 BST.
According to Visit Lincoln, the city is the only place in the world where you can find an original copy of Magna Carta together with the Charter of the Forest.
Votes for women
Children at the event are getting interested in the suffragette movement and its links with Magna Carta.
Here are some pupils from the Hythe School with an effigy of Emmeline Pankhurst.
Women's rights
The charter has inspired political movements over the centuries - not least the suffragettes.
Research by Alexander Lock on the British Library website found that in 1915, suffragette Helena Normanton argued the disenfranchisement of women contravened Magna Carta clauses 39 and 40.
And there's more on women's rights - Magna Carta clause 8 dealt with the rights of widows.
Puppet show
Adrian Harms
BBC Surrey
The Magna Carta 800 anniversary events continue at Runnymede.
I found these guys listening intently to the speeches a short while ago.
Freedom - what it means to you
Magna Carta famously dealt with the liberties of free men - and so we're asking what freedom means to you.
Tweet us @BBCSurrey or email us your comments. We'd love to know what you think.
'Magna Carta squatters'
Unofficial Magna Carta celebrations are also taking place today on Coopers Hill - by the inhabitants of Runnymede Eco-Village.
They are known as the Magna Carta squatters because of their proximity to the memorial.
They are facing eviction by landowners Orchid Runnymede - their hearing takes place at Guildford County Court later. We'll be bringing you the outcome here.
Magna Carta legacy
Professor Justin Fisher from Brunel University has put together an exhibition at Runnymede looking at the influence of Magna Carta.
He says the document inspired the Bill of Rights of 1689 in Britain, the Declaration of the Rights of Man and the Citizen of 1789 in France, and the Bill of Rights in the US in 1791.
He was in the second row for today's celebrations. Earlier, he tweeted that he would be presented to the royal party afterwards.
US dignitaries
An update on the Magna Carta celebrations from Get Surrey.
Eleanor Surrey Ad tweets: "The U.S. Attorney General is speaking at the memorial. I am proud, I am honoured and I am humbled."
See Get Surrey's live feed here.
Human rights 'distorted'
David Cameron called for fundamental reforms to UK human rights laws to "safeguard the legacy" of Magna Carta at today's ceremony.
He said the principle of Magna Carta was "as relevant today as it was then" but the notion of human rights in Britain had been "distorted and devalued".
The Conservative government wants to scrap the Human Rights Act and assert the supremacy of the UK's supreme court over the European Court of Justice in Strasbourg.
More hilarity
Karen Shakespeare has come up with another Magna Carta joke.
She tweeted: "Where did King John sign the #MagnaCarta? At the bottom. #crackerjoke"
Twitter has seen a deluge of Magna Carta comments during the ceremony. Some have been light hearted and others more serious.
One human rights activist wrote they felt elated to be alive to see this moment.
Queen leaves ceremony
Adrian Harms
BBC Surrey
The Queen has left the ceremony at Runnymede. The royal car was surrounded by crowds of people as it drove from the meadow.
Earlier, Her Majesty met people attending the celebrations. Thousands of people were there and a few lucky guests had the chance to meet her.
Rededication ceremony
Ben Cowell from the National Trust has tweeted a picture of the Magna Carta Memorial rededication.
The trust owns the Runnymede site which has been dubbed the "birthplace of modern democracy".
BBC iWonder: Power in your pocket
Living in Britain today, it's hard to imagine a time when nearly all of us had no say in how the country was run, or how our rulers governed us. That time was 800 years ago.
Before then, kings could do pretty much whatever they wanted. And they did.
But in the year 1215 their authority was challenged. The resulting agreement was called Magna Carta and changed the relationship between ruler and ruled forever.
Today, we can all challenge authority and digital technology gives us more opportunity to do that than ever before.
BBC iWonder looks at the power of the technology you can fit into your pocket.
Same spot 800 years later
The Queen and the Duke of Edinburgh were joined by the Archbishop of Canterbury Justin Welby and Prime Minister David Cameron at Runnymede earlier.
It all happened on the same spot where King John accepted the historic document that limited the power of the Crown in 1215.
Marking 800 years
One of the high profile moments from today's ceremony was David Cameron's speech.
He talked about British pride in Magna Carta and how its principles are held dear by many.
Many happy returns
Nicholas Davies has tweeted: "So thankful to be living in a country where the Government is not above the law.
"Many happy returns #MagnaCarta"
Queen unveils plaque
The audience are on their feet as the Queen walks across the stage to unveil a plaque.
She is now meeting people who are at the ceremony today.
We'll bring you pictures of the Queen as soon as we get them.
Principles 'shine brightly'
David Cameron says Magna Carta is something every person in Britain should be proud of.
He says its principles shine as brightly as ever.
"We hold these things dear and we should hold them even dearer for the fact they took shape here on the banks of the Thames."
You can also see a short video of part of his speech here.
Magna Carta 'relevant today'
Prime Minister David Cameron is speaking at the celebrations.
"What happened in these meadows 800 years ago is as relevant today as it was then.
"All over the world people are still struggling to live by the rule of law."
Memorial flags
The Union flag is displayed alongside the US stars and stripes on the memorial today.
Magna Carta has huge significance to a lot of Americans. Find out why here.
Speeches begin
Mark Carter
BBC Surrey
A hush has fallen over the meadow ahead of speeches by the Master of the Rolls and Prime Minister David Cameron.
More than 4,000 people have gathered in Runnymede for today's ceremony.
Queen follows King John route
David Starkey is at the event. "It's the kind of thing we Brits do so well," he says. "The whole thing is saying something important did happen and it's worth commemorating it."
He said the Queen, who had just arrived at Runnymede, had followed the expect route from Windsor taken by King John in 1215.
"I hope the Queen is in a better temper than King John would have been here 800 years ago. King John comes here dragged, furious, reluctant."
Google doodle
Today's Google doodle is an animation about Magna Carta.
It shows a line-up of barons with King John putting his stamp on Magna Carta after the deal is struck.
Art criticised
Hew Locke's new artwork is not to everyone's liking.
Alistair Pike has tweeted: "Putting out 12 chairs without a table isn't a #sculpture #MagnaCarta #BBCNews #art #chairs"
But tell us what you think. You can tweet us @BBCSurrey or email us.
Parade of flags
Adrian Harms
BBC Surrey
Events are taking place all over the meadow.
Here's a parade of flags by school children from Surrey - you can also see the video here.
Artwork unveiled
Adrian Harms
BBC Surrey
The Duke of Cambridge has unveiled The Jurors art installation at Runnymede.
See video of the artwork's official moment.
What does it mean?
More people quoting Tony Hancock on Magna Carta in these links tweeted by Joshua Rozenberg.
He writes: "The real meaning of Magna Carta. By @JackofKent jackofkent.com/2015/06/the-me… And by me (written last year) with video: bl.uk/magna-carta/ar…"
Reporting live
We are are not the only ones covering the events in Runnymede.
Get Surrey is providing live updates from the ceremony and performances too.
Empty chairs in use
Hew Locke's art installation has now been officially unveiled.
BBC Surrey presenter James Cannon caught up with the the artist a short while ago.
The chairs include a representation of the key to Nelson Mandela's jail cell door.
Prince arrives
Adrian Harms
BBC Surrey
Prince William has arrived - with a crew of photographers behind him.
For the royal party, The Duke of Edinburgh, the Duke of Cambridge, Princess Anne and her husband Vice Admiral Sir Tim Laurence will be at the event.
Children performing
Jack Fiehn
BBC Surrey Political Reporter
Children are performing something called the Freedom Game on the meadow.
It's based on Magna Carta themes of human rights.
Orchestra performing
Adrian Harms
BBC Surrey
The London Philharmonic Orchestra is now performing at Runnymede.
And there's not a spare seat in the house.
Land activists
Phil Coomes
Picture editor
Back to the Runnymede eco-village where photographer Daniella Zalcman stumbled upon the group in February this year, and, after a few phone calls, began to visit every week or so.
Here's a photo she took of a sign on the fence that surrounds the community.
Tony Hancock
"Does Magna Carta mean nothing to you? Did she die in vain?" asked an exasperated Tony Hancock playing the jury foreman in an episode of his famous Half Hour.
BBC legal correspondent Clive Coleman writes: "Clearly not. Far from dying, Magna Carta has had a life longer, fuller and more influential than the most optimistic medieval baron could have imagined."
Expensive ice cream?
Lots of Magna Carta jokes on twitter. For a light-hearted approach see these tweets.
Tony Munky wrote: "Can't believe it has been 800 years since the Magna Carta was signed - only feels like yesterday! #magnacarta"
And lots of jokes about ice cream. One here from Pongo The Penguin: "@mrchrisaddison Magna Carta? I thought that was an expensive ice cream with raspberry in it"
Cathedral light bulbs
It's not just Runnymede that is marking 800 years of Magna Carta though, events are taking place all over the country.
Take a look at this light installation at Salisbury Cathedral.
It has about 6,000 colour-changing light bulbs suspended from the ceiling to celebrate the 800th anniversary.
Plaque unveiling
Today's event will include speeches by the Archbishop of Canterbury Justin Welby and Lord Dyson, Master of the Rolls.
And the Queen will unveil a plaque at the memorial to mark the occasion.
Listen live
BBC Surrey is at Runnymede meadow and broadcasting live throughout the morning. Listen here.
Road and river closures
The river is closed for today's ceremony - not just the roads.
The A308 Windsor Road which runs alongside the meadow will remain shut until late afternoon, as will the section of the River Thames that runs through Runnymede.
For more details, see this information from the National Trust and Surrey County Council.
Voice of the people
In the run up to the anniversary celebrations, BBC Surrey asked a few people around the county if they knew what Magna Carta was.
One woman said: "Didn't that happen in 1066 in Hastings?" Another said: "Wasn't it the Domesday Book?"
Someone speculated that it might have been a document signed somewhere between 1400 and 1600. If you're stuck, look at BBC iWonder.
'Magnificent irony'
Briony McDonagh has tweeted: "Runnymede Eco Village residents in court over eviction proceedings on the day of the #MagnaCarta celebrations in the field next door"
And she posted: "Someone, somewhere has a magnificent sense of historical irony #MagnaCarta #MagnaCarta800 #freetheland"
That hearing begins at 10:30 BST. We might find out the outcome while the ceremony is under way.
Visiting dignitaries
We're waiting for the national Magna Carta Foundation of Liberty ceremony to get under way at 09:00 BST.
Invited guests include members of the Royal Family and dignitaries from the UK and around the world.
More than 4,000 people are gathering on the normally tranquil meadow.
Foundation of US democracy
William Hubbard, president of the American Bar Association which put up the Magna Carta memorial in 1957, is at the celebrations. He said: "We could not be more excited. We are thrilled."
He said about 900 ABA members had come over to the UK to celebrate Magna Carta.
"It's the foundation of American democracy. It's absolutely the foundation of our country."
'Beautiful, intricate design'
National Trust director Dame Helen Ghosh loves how the chairs represent all eras and all continents in terms of liberty and the rule of law.
She says: "They're so intricate. The amount of time you could spend just gazing at the design is wonderful."
Artwork unveiled
And here's the first view of Hew Locke's artwork - inspired by Magna Carta's principles of justice.
It shows 12 chairs arranged in a square - and it's called The Jurors.
Have you read it?
Sister Catherine Wybourne has tweeted: "I hope all those writing about Magna Carta today have actually read it.
"Sometimes one gets the impression some haven't. #MagnaCarta"
If you're not in a position to read the original medieval Latin on parchment, there are some handy translations around.
Here's one from the British Library, but remember it was amended and edited over the years.
Preparations on meadow
Jack Fiehn
BBC Surrey Political Reporter
All around me preparations are taking place for the main event in a few hours time.
There are tents all around the field and a huge stage with seats in front of it.
That's where the Queen and other members of the Royal Family will be later on this morning for speeches and music.
'So it begins'
The National Trust has tweeted a picture of the first guests arriving - under overcast skies although the weather is expected to brighten later.
The organisation wrote: "And so it begins... #MagnaCarta800"
Good morning
Tanya Gupta
BBC News
Welcome to our live page marking the 800th anniversary of the Magna Carta.
I'll be bringing you all the latest from the ceremony at Runnymede, where thousands of people including the Queen are gathering to mark the event.
You can tweet us @BBCSurrey and email us your pictures and comments.