A hundred days until London hosts the Olympic Games. A hundred days until the starting gun fires on three weeks of sporting agony and ecstasy. But is London ready?

"It signifies, first of all, still an extraordinary amount of work still to do, but I think 100 days, it means something to people," noted two time Olympic gold medalist Sebastian Coe, chairman of London 2012. "When you're talking about seven years, six years, five years, four years, but actually when you're really talking about days, and we're talking 12 Wednesdays or something, I mean it really is, it's very close.

The Olympic Park is complete, barring the final furnishings.

Synchronized swimmers are already practicing in the pools. The striking Aquatic Center is ready for the likes of American swimmer Michael Phelps, who will try to build on his record 14 Olympic golds. 

Beneath the sweeping curve of the Velodrome roof, Britain’s cycling stars are already charging round the track.

Beyond east London’s Olympic village, other venues are taking shape - like the beach volleyball court in the shadow of Parliament. 

International Olympic Committee President Jacques Rogge gave his verdict to Britain’s Prime Minister David Cameron after visiting the venues.

“There is already, before the Games begin, a great legacy in east London, a great legacy of the sports venues and this is a tangible legacy. To conclude, prime minister, we are a happy International Olympic Committee. Thank you very much,” Rogge said. 

But amid the anticipation, there are murmurs of discontent. On two separate days this week, immigration lines at Heathrow, London’s main airport, reached well over 90 minutes. Travelers posted photos and vented their anger on the Internet. 

An oversight committee of MPs warns that Olympic visitors could face being held on board aircraft or stuck in lengthy immigration lines. The government insists it will be ready. A temporary terminal has been built especially for Olympic competitors. 

Once through the airport, there are fears travelers could face gridlock on London’s roads and subways during the Games. 

There are concerns, too, over security. 

In recent weeks anti-terror squads have been practicing on the streets, in the skies and underground. In a late addition, the ministry of defense is providing 13,500 soldiers for the Games. Total security staff numbers are now estimated at 23,700. The security budget has doubled to $882 million. Security analysts like David Rubens are voicing fears that London could be on lockdown.

“It’s very difficult to maintain the balance between an open and welcoming event and security management," Rubens said. "It’s different from what happened in Vancouver, it’s certainly different from what happened in Beijing. And the people responsible will be lying awake at night trying to wonder whether they’ve got that balance right, and the answer is, if it goes wrong, then you got it wrong.”

That answer will be known in 100 days. 

For London, for the competitors, for the 300,000 expected visitors - the countdown is on.