Kew Gardens on an English spring morning will host the first in a series of celebrations on Wednesday to commemorate the 100 days' countdown to the London Olympics.
An oak tree will be planted to mark Britain's role in the birth of the modern Olympic movement and giant Olympic rings made up of 25,000 flowers will be on display.
A city steeped in theatre and pageantry will then be entertained in the early afternoon by members of West End theatre shows assisted by British athletes taking part in a "West End Warm-Up" performance in Trafalgar Square.
On the following day the 70-day Olympic torch relay begins at Land's End.
Any initial trepidation about Britain's ability to stage a major global event has long vanished and last month the London organising committee received a glowing endorsement from International Olympic Committee commission chairman Denis Oswald who proclaimed: "London is ready to welcome the world."
"We can feel that London is feeling the fever of the Games," Oswald said. "We are in no doubt that this summer will be a summer like no other in Britain."
Ensuring a unforgettable Olympics for London and the thousands of athletes and visitors who will pour into Britain for the Games opening on July 27 is the ultimate responsibility of organising committee chairman Sebastian Coe.
A reminder of the disturbing ease with which big sporting events can be disrupted came this month when an intruder in the Thames disrupted the annual university boat race between Oxford and Cambridge.
The torch relay, as the pro-Tibet protesters demonstrated during the 2008 Beijing Olympics relay, is similarly vulnerable as are the street races such as the marathons and walks.
In an interview with Reuters to mark the 100 days' landmark, Coe said there was a need to get a balance between the safety of the competitors while ensuring spectators were not subjected to oppressive security measures.
"Competitors are doing something at the highest level, they have devoted over half their young lives to be there," he said.
"It is our responsibility to make sure they have a secure environment in which to compete but you do not want people coming to London feeling they have come to a siege town.
"We will get that balance right, we have to get that balance right. I am not being remotely cavalier or particularly sanguine about the nature of what we have to do but we will get this right."
Coe was also upbeat about London's problematic transport system.
"At Games time things will be different," he said. "This is the first time a Games will have been on these shores for 64 years and there's nobody in this room, there's probably nobody sitting out there now that is going to is going to witness them again in their lifetime so it is a celebration.
"The city will look different, it will be different, getting about it will be different."
Asked about criticisms of the high cost of a sports event in grim economic times, Coe said there would be some validity to the argument if the Olympics was just a sporting festival.
"But of course it isn't," he said. "We have regenerated in the process a large part of east London, we've transformed the lives of many young people living in east London.
"More broadly we have an opportunity to showcase this country in front of four billion people not just in sport but in our cultural communities. We have the ability to host 200 countries.
"There are millions of people the length and breadth of the country who are now helping us to deliver these Games. We have a torch relay that's going to go within 10 miles (16 kms) of 95 percent of the population.
"So this goes way, way beyond just 16 days of sport."
London Olympic organisers will on Wednesday hold a series of events to kick off the Games' 100-day countdown as preparations for the showpiece event enter the final straight.
The milestone will be marked across the country and internationally with a host of ceremonial activities and an array of test events to iron out any operational problems before the flame is lit on July 27.
London 2012 chief executive Paul Deighton insisted that preparations were on course with dress rehearsals for Wheelchair Rugby, Synchronised Swimming and Shooting all set to begin on Wednesday.
Olympic fever will spread beyond Britain's borders as expats around the globe join in the countdown.
In the United States, former heavyweight boxing champion Lennox Lewis will lead one hundred cyclists and an open top London double decker bus on a ride down Miami's South Beach.
One hundred British Embassies and High Commissions will hold events with Turkey, Venezuela and New Zealand all entering into the Olympic spirit, Britain's Foreign Office revealed on Tuesday.
There will also be a series of 100 metre races at Berlin's Brandenburg Gate, the 1984 Olympic Stadium in Sarajevo and in the Palace Square in St Petersburg.
"I'm delighted that British Embassies around the world have come together to mark 100 days to go to the opening ceremony of the greatest show on earth," said Foreign Office Minister for the Olympic and Paralympic Games Jeremy Browne.
Organiser Deighton insisted the British capital was well-prepared to become the world's focal point.
"We are absolutely where we want to be with 100 days to go - we are ready to welcome the world to London," he said.
"Millions of people around the UK are getting ready to celebrate the biggest event in sport."
Queen Elizabeth II will open the Games, giving London the honour of being the first city in the modern era to host the Olympics three times, having already held them in 1908 and 1948.
The event is set to give Britain's ailing economy a much needed boost, but the general mood of austerity will be reflected in the Games, albeit to a far lesser extent than in 1948, when competitors were housed in military barracks and university dormitories.
Organisers conceded long ago that, despite a budget of £9.3 billion ($14.8 billion, 11.2 billion euros), they would be unable to compete with the spectacle provided by the 2008 Beijing Olympics.
Instead, the opening and closing ceremonies will bring to together the country's most creative minds to produce a celebration of Britishness.
Responsibility for the opening ceremony lies with 'Slumdog Millionaire' director Danny Boyle, who has promised a fitting curtain-raiser before 10,500 competitors from 204 countries do battle.
However, two substantial hurdles still loom.
Doubts remain about how London's already stretched transport system will cope with ferrying spectators and athletes around the congested city.
Also, there are fears over whether Britain's security services will be able to prevent incidents such as the bloody hostage-taking of athletes at the 1972 Munich Olympics and the bombing of the 2004 Atlanta Games.
Some £6.5 billion has been spent on modernising the transport system, including the world's oldest underground train system, and 48 kilometres (30 miles) of Olympic road lanes should help speed the travel of VIPs.
Security has cast a shadow since the day after London was awarded the Games, when suicide bombers killed 52 people on the transport system.
Security expert David Hunt, from the Exclusive Analysis think-tank, warned that the main threat by jihadist militants was likely to come from domestic, lone wolf actors.
A combined force of more than 40,000 soldiers, police and private security guards will be mobilised for what Prime Minister David Cameron called the "biggest and most integrated security operation in mainland Britain in our peacetime history".