Olympic organisers trying to keep London's opening ceremony secret have appealed to rehearsal spectators and performers not to leak details of the event that insiders describe as spectacular with a touch of quirky British humour.
At a rehearsal on Monday night, Oscar-winning film-maker Danny Boyle asked some 30,000 spectators not to post details or photos on social networks of his 27-million-pound ($42-million) ceremony - and most honoured his plea, with few ''secrets'' buzzing online on Tuesday.
Boyle has voiced frustration at details leaking before Friday's show, particularly after he unveiled part of the set last month to sate growing curiosity.
But the explosion of social media has made secrets almost impossible to keep at this Olympics.
In a move to counteract leaks, organisers emblazoned a Twitter hashtag #savethesurprise on screens inside the Olympic Stadium on Monday, urging people to use that tag to build a buzz before Friday, and participants hoped this would work.
''The ceremony is very emotional, very British, with quirky humour. And it will have surprises, even for the critics,'' said Dikaia Chatziefstathiou, who researches the Olympic movement at Canterbury University and is dancing in the opening ceremony.
Chatziefstathiou said the 10,000 volunteer performers in the three-hour ceremony signed contracts stopping them from giving away details or posting photos onto social network sites, but she was allowed to say the show spanned 1896 to the present.
Organisers will be hoping that a spectacular opening will end complaints from Britons about security bungles, transport woes and the 9.3-billion-pound ($14.4-billion) cost of the Games, being held as Britain faces recession and unemployment of 8.1 per cent.
The ceremony poses a challenge to organisers to strike a balance between global and national appeal.
Beijing in 2008 was determined to use an opening ceremony watched by about one billion people to forge a new identity as a modern, global powerhouse on the world stage and produced a lavish, meticulously choreographed show.
Athens in 2004 used its event and hosting of the Games to try to shed its reputation as a parochial and unruly corner of the European Union, while Sydney in 2000 showcased its appeal as a sophisticated tourist destination, and not just the outback.
With another 60,000 people to attend a dress rehearsal on Wednesday, organisers were finding it difficult to keep a lid on their plans.
Hundreds of people took to Twitter and Facebook after Monday's rehearsal to rave about the event, describing it as ''out of this world'', ''bonkers'', with some sarcastic silliness and a ''mind-blowing finale''.
Some details are already known about the ceremony that will be watched by about a billion people globally, although at Monday's rehearsal key moments were missing.
''We can't show you everything,'' Boyle said in a brief introduction to the stunt-filled show.
''If you would not tweet and you would not post, especially pictures, we would really, really appreciate it.''
The ceremony, titled 'Isles of Wonder' and inspired by William Shakespeare's play 'The Tempest', is due to open at 2000 GMT with the ringing of the largest harmonically-tuned bell in the world.
Queen Elizabeth will open the Games in front of more than 100 world leaders and US first lady Michelle Obama.
Boyle, who made the gritty film 'Trainspotting', revealed last month that he will turn the stadium into a British rural idyll complete with live sheep, horses, cows, goats, chickens, nine geese and three sheep dogs - much to the disapproval of some animal rights groups.
The pastoral scene will also include a game of village cricket and music festival style ''mosh pits'' filled with standing members of the public at either end of the stadium.
What the media has since leaked includes elements of the next ''act'' of the show, recreating the ''dark Satanic mills'' of William Blake, whose poem Jerusalem includes this reference to the Industrial Revolution and has become an anthem to England.
Insiders said the industrial revolution was the second of three chapters in the show that then moved on to present day.
This final section includes a tribute to the National Health Service and nurses, with reports that Harry Potter villain Voldemort and the magical nanny, Mary Poppins, would appear.
After Boyle's show, athletes from the 204 competing nations will walk around the meadow, with bookmaker Coral running odds of 100-1 that a streaker would appear during the evening.
The identity of the torchbearer who lights the cauldron is the most closely guarded secret and, so far, has not leaked.
Bookmakers have the clear favourite as Steve Redgrave, Britain's most successful Olympian who won five gold medals.
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