Time stood still as London marked the 500-day Olympic countdown with an embarrassing malfunction.
The giant digital clock displaying the days, hours, minutes and seconds until the Olympic opening ceremony on July 27, 2012, froze Tuesday afternoon — just a day after its glitzy unveiling steps from Nelson's Column in Trafalgar Square.
While the clock was restarted several hours later, it was a humbling setback for London organizers at a milestone moment that was meant to showcase the city's Olympic readiness and know-how. There were also teething troubles as 6.6 million tickets went on sale.
"Whilst the clock has stopped ... it does not give us additional time to stage the games," the London organizing committee said after the steel clock's big red numbers halted at 500 days, 7 hours, 6 minutes, 56 seconds.
The clock — which measures 8.5 meters (27 feet) high and 5 meters (16 feet) long — had started ticking down after a ceremony Monday evening in the popular central London square.
Omega, the Olympic sponsor which made the clock and is part of Swatch Group AG, blamed the problem on a "technical fault." it was fixed by early Tuesday evening.
"It's one of those windups set to test us, but it's working again," said Sebastian Coe, head of the Olympic organizing committee.
The clock was cordoned off by white tape as three workers tried to fix the problem. At one point, the numbers changed and the clock showed 201 days to go, then 208. Eventually, it went blank.
As word spread, onlookers began to crowd around the faulty clock, staring and taking pictures. There were more people on the site Tuesday than there were for Monday's unveiling attended by organizers, city officials and British athletes.
"It's about right for Britain, really," said Dawn Woods, a restaurant manager from Nottingham in central England. "It's a clock — you'd think it would be simple to get right."
By coincidence, the breakdown of a countdown clock was the storyline in a spoof documentary on the London Olympics aired by the BBC this week.
Earlier Tuesday, a few hours into the online ticket launch, fans with Visa credit cards which expire before the end of August found they were unable to process their orders. Visa is an Olympic sponsor and the only card that can be used to purchase tickets.
"It is an issue with Visa rather than the website or our systems," the London 2012 organizing committee said.
London 2012 said the expiration rule was clearly stated in the website and ticketing guide.
"There is no glitch with the website," the committee said. "The expiry date is made clear in all of our materials — if your Visa card expires before August 2011, you will not be able to process your application. Visa is working to extend this to allow more people to apply."
Organizers were at least relieved the system had not crashed. They had braced for a crush of demand, even though the tickets are not being sold on a first-come, first-served basis.
"We're pretty pleased," Coe said. "It's a big technological bit of action. We've come through pretty well. Sales have been good, steady."
Customers can apply for tickets over a six-week period ending April 26, with no advantage to signing up early. Any oversold tickets will be distributed via a ballot, or lottery, system. Tickets will be allocated by June 24.
Tickets are available for 645 competition sessions across 26 sports, with prices ranging from 20 pounds ($32) for some events to 750 pounds ($1,200) for the men's 100-meter final to 2,012 pounds ($3,215) for top seats at the opening ceremony.
Two of the greatest athletes in Olympic history came to London to help celebrate the countdown.
Nine-time track and field gold medalist Carl Lewis and five-time gymnastics champion Nadia Comaneci joined Coe — a former Olympic champion — for a series of events across the capital.
"It's happening," said Lewis, the American sprinter and long jumper who competed in four Olympics. "It's wonderful to get the bid. It's wonderful to know what's coming. But today you can actually start your opportunity to be a part of it, because in 517 days or so it will all be over.
"Today is the first day of the Olympics when it really comes down to it."
Comaneci, the Romanian who scored the first perfect 10.0 in modern Olympic history when she won three golds at the 1976 Montreal Games at the age of 14, said she looks forward to coming back next year to watch the gymnastics and soak up the atmosphere.
"I always say when the Olympics are happening, you shouldn't be in any other place in the planet — you should be here," Comaneci said.
Britain is spending 9.3 billion pounds ($15 billion) to build new venues and regenerate an industrial wasteland in east London into a vast Olympic Park.
"This isn't the finishing straight, but we're in the back straight of the 800," said Coe, a former 800-meter record holder who also won two Olympic gold medals in the 1,500 meters.
While demand will be huge for the 100-meter final, Lewis urged fans to consider buying tickets to some of the lower-profile events.
"I've been to four Olympic Games since I retired," he said. "Every time I've gone to two new sports that I've never seen before. I think it's a unique opportunity to go see team handball, or badminton or volleyball. It gives you the opportunity to experience something else. You may end up watching badminton so much you may end up taking up the sport yourself."
AP Sports Writer Rob Harris contributed to this report.