The London Olympics will open one year from today amid the stunning and historic backdrops of the Houses of Parliament, the Tower of London and Buckingham Palace - some of the monuments that make the city one of the world's most popular destinations.
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On July 27, 2012, London will welcome 10,500 athletes from more than 200 countries, 5,000 officials, 20,000 media personnel and hundreds of thousands of visitors for a 17-day extravaganza featuring 26 sports at 32 venues.
"With a year to go we can safely say we are ready to welcome the world," said Boris Johnson, the London mayor.
Venue construction is largely completed, tickets are almost sold out, and the government says the games will come in under the £9.3 billion (Dh56bn) budget.
Competition will be held in memorable venues and locations - Usain Bolt sprinting down the track in a new, 80,000-seat Olympic Stadium, beach volleyball players duelling on the sand in Horse Guards Parade, triathletes splashing in the Serpentine in Hyde Park, Roger Federer and Rafael Nadal stepping back on to Centre Court at Wimbledon, archers firing their arrows at Lord's cricket ground and showjumpers clearing fences at Greenwich Park.
Security is a big concern, but London organisers don't want that to stop these Games from being a big party.
The Beijing Olympics were marked by an efficient yet sterile atmosphere, but London promises knowledgeable fans, packed venues, "live sites" with giant screens around the city and a "home" crowd of citizens from diverse nationalities, cultures and backgrounds.
It will all kick off with an opening ceremony created by the Slumdog Millionaire director Danny Boyle.
"It won't be the same as Beijing," Johnson said. "I've always said it would be different. It would be splendid. It would be brilliant. It would be brilliant in an entirely different way.
"Wait till you see that opening ceremony. I think you will be weeping tears of joy. That's my confident prediction."
While Athens struggled to the last minute to finish venues for the 2004 Olympics, and Beijing was battered for its record on Tibet and human rights ahead of the 2008 Games, London has enjoyed a comparatively smooth and crisis-free ride so far.
On the downside, the British public has complained bitterly about the ticket sales process, and London's strained public transport system faces challenges to keep the city moving smoothly during the games.
Lord Coe, the organising committee leader and two-time 1,500-metre Olympic gold-medallist and former 800m record-holder, surveys the year ahead like a runner entering the "midway back straight" on the final lap.
"I know from 800s that's where it's won and lost," Coe said. "I don't kid myself. This is a crucial part of the race, and how you come out of that 500 to 600 [metres] often determines how you come across the line."
Today, London will mark the year-to-go milestone with a televised ceremony from Trafalgar Square, with Jacques Rogge, the International Olympic Committee (IOC) president, on hand to formally invite the world's athletes to the Games.
Organisers will present the design of the Olympic medals and, in the Olympic Park, the British medal hopeful Tom Daley will perform the first dive into the Olympic pool.
"If we compare with previous games, we are well advanced and this is a very comfortable position," said Denis Oswald, the Swiss IOC executive-board member who leads the coordination commission for London. "This is especially the case when you don't have to worry about construction and you can really concentrate on the operations side."
Olympic organisers say 88 per cent of the venues and infrastructure work for the Games has been completed. The Olympic Park in Stratford has a set of gleaming new venues, including the main Olympic Stadium, the velodrome, handball arena and temporary basketball arena. The aquatics centre, with its sweeping, wave-shaped roof, will be formally completed on Wednesday.
Over the next 12 months, organisers will install the track in the stadium, dress up the venues, finish the landscaping and complete the Olympic village on the edge of the park. The 226-hectare site is the centrepiece of a massive regeneration project that is turning a former industrial wasteland into a huge urban park. Bordered by a giant new shopping centre and new transport links, the park is designed to serve as a vibrant residential neighbourhood after the 2012 Games.
The future of the £486m stadium remains in dispute. The Olympic Park Legacy Company selected West Ham United football club to take over the arena after the games. But rival London club Tottenham Hotspur, which proposed taking down the stadium and building a new one without the running track, is challenging the decision in court.
Ticketing remains a sore point. With 6.6 million tickets available to the British public, organisers received 22 million requests in a heavily-criticised lottery-style allocation; 1.2 million applicants received no tickets at all. Another 750,000 tickets were sold in the first phase of the second sales. A total of 3.5 million have now been sold, with tickets remaining only for football, volleyball and wrestling.
"No city has ever sold tickets at that rate," Coe said. "No games, no sporting event in my lifetime can point to that kind of demand. But I don't for one minute diminish or dismiss the level of disappointment."
The IOC singles out transportation as London's biggest Olympic challenge.
Organisers are calling these the "public transport games", with spectators travelling to venues by Underground, bus and the new high-speed "Javelin" rail service between St Pancras station and Stratford.
Billions of pounds have been invested in public transport upgrades. Underground strikes have not been ruled out. A system of Olympic traffic lanes and routes is still being finalised.
"Transport is a challenge in London in normal times, as well, so when you add 300,000 people who are moving from one place to another, it doesn't help the situation," said Oswald, the IOC member.
Citing the transportation problems that marred the 1996 Atlanta Olympics, Coe said London's reputation would be severely damaged if the Games are mired in traffic gridlock and travel chaos.
"We know this has to work," Coe said.
Underpinning the sports festival will be one of the biggest security operations ever mounted.
Security at the Olympics has been a critical issue ever since the 1972 Munich massacre, even more so after the September 11, 2001 terror attacks. A day after London was awarded the games in 2005, suicide bombers attacked London's transport network, killing 52 people.
The British government is planning for the national terror threat to be "severe" during the Olympics, meaning an attempted attack is highly likely.
Security screenings for spectators will be tight and widespread, with airport-style checks at most venues. Away from the competition sites, protecting the Underground subway network and public places will be a major challenge.
"We're already seeing chatter from terror groups regarding the 2012 Games but none of it seems defined at the moment," said a British security official, speaking on condition of anonymity because of the sensitivity of his work.
"This is to be expected, though, with an event of this magnitude."
About 12,000 police officers will be on duty each day of the July 27 to August 12 games, which have a security budget of £475m.
British officials say the country has the experience and know-how in dealing with terrorism.
"I am as sure as you can possibly be one year out from a games that we have done everything that we need to deliver a safe and secure games," said Hugh Robertson, the Olympics minister.
Extra surveillance cameras will also be installed around the games. Britain has some of the most extensive surveillance powers in the world and has become a leader in what critics call "Big Brother" techniques; more than 4.3 million closed-circuit cameras are in operation.
All Olympics workers will be put through a vigorous screening, including checks for terror contacts and other criminal offences.
Organisers are determined to keep security from being overwhelming. They point to the successful policing of the royal wedding in April of Prince William and Kate Middleton, when a million people lined the procession route from Westminster Abbey to Buckingham Palace.
"We're very good at policing in a friendly and a discrete way," Coe said.
"The real challenge is to maintain security to protect the athletes, protect people, protect assets, but at the same time having people leaving your city feeling they haven't been pushed from pillar to post."
The Olympic venues
Unlike Beijing’s stadium, the showpiece of Olympic Park has a simpler design, drawn up with a view to scaling it down after the Games. The upper tier can be dismantled, leaving a 25,000-seater sunken bowl. The football club West Ham United are the preferred bidder to take over the venue.
Sports Track cycling
The lower tier has 3,500 seats, with the rest suspended in two upper tiers under the curved roof. In between, a glass wall will allow people to watch the action from outside. Shortlisted for the Stirling Prize, Britain’s most prestigious architecture award, the venue, pictured, is the most sustainable venue in the Olympic Park.
Sports Diving, swimming, synchronised swimming, water polo, modern pentathlon
Designed by the architect Zaha Hadid, the centre has a wave-like roof. It contains a 50m competition pool, a diving pool, and a warm-up pool. One of the few Olympic-sized pools in Britain, it will be scaled back to 2,500 seats after the Games. It has a temporary, 5,000-capacity water polo venue.
The main pitch will hold 15,000 fans, with the second pitch having 5,000 seats. Pitches to be installed by September, with the structures built by March 2012. The centre will have two pitches, one for use as a warm-up area.
Sports Basketball, handball
The fourth-largest venue in the park and one of the largest temporary venues built for any Games. The frame of 20 steel arches is wrapped in fabric to form the canvas for a lighting display. After the Olympics, parts are expected to be reused or relocated elsewhere in Britain.
All England Club
The home of the Wimbledon championships will host the entire tennis tournament. Centre Court, dating back to 1922, has a 15,000-seat capacity and a retractable roof, enabling play during rain or bad light. Court One can host 11,500 spectators. The club hosted the 1908 Olympics at its pre-1922 venue.
North Greenwich Arena
Sports Gymnastics (artistic, trampoline), basketball
Once known as the Millennium Dome, this arena lay idle for years after the Year 2000 exhibition. Eventually taken into private hands, it was transformed into a sports and entertainment arena with shops, restaurants, a nightclub and a cinema. The main arena will seat 16,500 for the gymnastics, with the full capacity for the basketball finals.
Sport Badminton, rhythmic gymnastics
The concert venue, next to Wembley Stadium, was built for the 1934 Empire Games’ swimming events. The August 2011 Badminton World Championships will act as a test event at the facility.