The torch relay is on the last leg of its 70-day journey - along the River Thames
The opening ceremony of the London Olympics is just hours away after seven years of preparations.
The three-hour spectacle in the Olympic Stadium will be viewed by a global TV audience of around a billion people.
The day of celebration began at 08:12 BST with a mass bell ringing. Big Ben rang for three minutes for the first time since King George VI's funeral.
Lord's cricket ground has turned away spectators trying to get in to watch archery amid confusion over ticketing.
The London 2012 website advertised the event's preliminary rounds as "unticketed", which some members of the public interpreted as open to the public.
But Olympic organiser Locog said it had not advertised or sold tickets for the ranking event and had always made it clear preliminary rounds were not open to spectators.
South Korea later claimed the first two world records of London 2012 in the men's team and individual archery.
Meanwhile, the Olympic flame has arrived at City Hall on the Queen's rowbarge Gloriana after first weaving through the maze at Hampton Court Palace and being carried along the Thames on the final day of the torch relay.
The flames's 70-day nationwide journey ends with the lighting of the cauldron during this evening's opening ceremony but the identity of the person who will take on the honour remains a mystery.
In other developments:
- Three people due to work as staff at an Olympic venue in Newcastle were arrested on Wednesday on suspicion of immigration offences following accreditation checks
- Culture Secretary Jeremy Hunt narrowly avoided hitting a group of women with a handbell after it flew off the handle on HMS Belfast during the co-ordinated ringing - he called the moment a "classic"
- American First Lady Michelle Obama, who is in London to lead the US delegation, told the US Olympic team at their Docklands training camp "have fun, breathe a bit, but also win"
- International Olympic Committee president Jacques Rogge praised the regeneration which has taken place in east London and said the Games would have a "tangible legacy" with, uniquely, "no white elephants"
- About 30 people are staging a "justice for Bhopal" protest at the Olympic Park entrance - a reference to a 1984 gas leak disaster in India - to object to Dow Chemical's sponsorship of the Games. Dow bought the Union Carbide Corporation - whose subsidiary ran the Bhopal pesticide plant - in 1999
- London taxi drivers who were to protest at Hyde Park Corner over their exclusion from Olympic traffic lanes have been banned by the Metropolitan Police
Prime Minister David Cameron said Britain was ready to welcome "the greatest show on earth".
Speaking in Downing Street, he said: "It's a great opportunity to show the world the best of Britain, a country that's got an incredibly rich past but also a very exciting future.
"Someone asked me yesterday what face of Britain do we want to put forward - is it Blur or the Beefeaters? - and frankly it's both."
The chief executive of the Olympic Delivery Authority, Dennis Hone, said he was thrilled the big day was finally here.
He told BBC Radio 5 live: "When you look around at the park, you look at the venues, the 100 hectares of landscaping, the 2,000 trees, all the plants in bloom, it's looking fantastic. It's going to be a great day, it's going to be a great 17 days of sport."
Mayor of London Boris Johnson told the programme: "What's so amazing is just the wave of excitement seems to pass from person to person like some benign form of contagion. Everybody is getting it."
US First Lady Michelle Obama has given her own personal good luck message to Team USA
Organisers of Oscar-winner Danny Boyle's opening ceremony have released a video clip giving a sneak preview, featuring groups in colourful stage outfits dancing to Tiger Feet by 1970s rock group Mud and cyclists with wings pedalling along to Come Together by the Beatles.
Europe's largest bell will ring inside the Olympic stadium at 21:00 BST at the start of the £27m extravaganza, featuring a cast of 10,000 volunteers and said to be a quirky take on British life.
Some 15,000 square metres of staging and 12,956 props will be used, and the event will boast a million-watt PA system using more than 500 speakers.
The crowd of about 80,000 will include the Queen and a host of dignitaries and celebrities.
As late as Thursday night, Games organisers said that the ceremony had not sold out and tickets in the two highest price categories - costing £2,012 and £1,600 - were still available.
The Queen and Prince Philip will host a Buckingham Palace reception for heads of state and government and an opening ceremony celebration concert featuring Snow Patrol, Stereophonics, Duran Duran and Paolo Nutini will be held in Hyde Park.
More than 10,000 athletes from 204 nations will take part in the London Olympics. Some £9bn of public money has been spent on staging the Games.
Coverage of the opening ceremony starts on BBC One at 19:00 BST and Radio Five Live from 18:00 BST. UK users can also watch it via the BBC News website.