|The aquatics centre takes pride of place amid the tower blocks of east London [GALLO/GETTY]
With one year to go until the opening ceremony of the London 2012 Olympics, organisers completed the last of their permanent venues on Wednesday and promised to put on a safe and spectacular event that will captivate the world.
Ahead of an evening ceremony in Trafalgar Square, the $442 million aquatics centre was opened on a former industrial wasteland in the East End that has been transformed by one of Britain's biggest building projects in history.
"It's a pretty big moment for us," organising committee chairman Sebastian Coe said.
"Though a mountain of work is still needed to prepare (the venues) we have an extraordinary platform to build on ... I don't think we are sitting here fearful of anything. We have everything under control."
International Olympic Committee (IOC) president Jacque Rogge was in London to formally invite the world's athletes to the Games – with few of the distractions that overshadowed the one-year countdowns to the previous two.
Beijing was battered for its record on Tibet and human rights before the 2008 Olympics, while Athens struggled to the last minute to finish venues in 2004.
Even the worst global recession for more than 70 years failed to significantly derail London's plans, with test events already underway and the IOC relaxed about the final 12 months before the Games returns to London after 64 years.
Security and transportation remain the biggest challenges.
The British government has been planning for the national terror threat to be classified as "severe" during the Olympics, meaning an attempted attack is regarded as highly likely.
A day after London was awarded the games in 2005, suicide bombers attacked London's transportation network, killing 52 people.
"Security is permanently under review," Coe said Wednesday.
"We have the right teams in the right place. We will do whatever we have to do to provide a safe and secure Games."
"The key is finding the right balance," he added.
"We do big events pretty well in this country. We want people to feel welcome without the city being locked down."
The latest milestone will be marked Wednesday evening by 17-year-old Tom Daley taking the first dive in the Olympic pool.
The 17,500-capacity venue, which will also be used for swimming, synchronised swimming and water polo events, had been expected to be among the first major projects to be finished and one of the boldest architectural statements on the 226-hectare (560-acre) east London site.
Instead it was completed after the 80,000-seat Olympic Stadium, the velodrome, handball arena, basketball arena and the International Broadcast Centre.
The aquatics center design was scaled back in an effort to cut spiraling costs even before Britain slumped into recession.
While retaining the sweeping, wave-shaped roof, the size of the venue was reduced to prevent it becoming a white elephant after the Games have finished, with two giant wings of temporary seating to be added to accommodate fans during Olympic competition.
Filling venues has not proved to be a problem. In fact, "a world record-breaking demand for any sporting event on the planet" – according to Coe – has provoked anger about the ballot process for tickets.
"The problem here is essentially that we had 22 million applications for 6.5 million tickets," Olympics minister Hugh Robertson said.
"One in four people are going to be disappointed and there's nothing we can do about that. If we'd built stadia of twice the size, we'd have faced huge international criticism for building white elephants that couldn't be used afterwards."
A year from now, London will be welcoming 10,500 athletes from more than 200 countries, 5,000 coaches and team officials, 20,000 media personnel and hundreds of thousands of visitors.
The 17-day festival will feature athletes competing in 26 sports in more than 300 medal events in 32 venues.