The Queen praised the "uplifting spirit" of the Paralympic Games on Wednesday night as she launched the sporting spectacle featuring disabled athletes from across the world.
Hundreds of men and women who have trained for years to compete at London 2012 will soon be in action - a first for some at the global event.
The Queen completed her own milestone by opening a Paralympics for the first time - uttering the words: "I declare open the London 2012 Paralympic Games".
A vibrant and imaginative opening ceremony staged in Stratford's Olympic Stadium heralded the beginning of the sporting event and featured Professor Stephen Hawking, who has motor neurone disease, a host of famous Paralympians and hundreds of volunteers.
The Queen extended greetings to the visiting athletes and looked forward to the 11-day spectacle that begins on Thursday.
In a statement released earlier in the evening she said: "It is with tremendous pride that the people of London and the United Kingdom welcome the world to the London 2012 Paralympic Games.
"The Games are returning to the country where they first began, more than 60 years ago.
"We look forward to celebrating the uplifting spirit which distinguishes the Paralympic Games from other events, drawing on Britain's unique sporting heritage."
When she first appeared in the Olympic Stadium the Queen was greeted by huge cheers and applause from the sell-out audience of more than 60,000 people.
Dressed in a pale blue and champagne dress and coat by Angela Kelly, she smiled at the warm greeting.
Her arrival was more conventional than her dramatic entrance at the Olympic Games opening ceremony, when she appeared to parachute into the arena with James Bond.
The Queen travelled to the stadium ahead of the start of the spectacular ceremony for a reception with senior figures from the International Paralympic Committee (IPC).
And she was escorted into the arena by the IPC's president, Sir Philip Craven, who competed in five Paralympic Games from 1972 to 1988.
Missing from the Queen's side was the Duke of Edinburgh, who is convalescing after a recurrence of a bladder infection.
But standing nearby were the Duke and Duchess of Cambridge, both ambassadors for ParalympicsGB, and the Earl and Countess of Wessex.
Kate looked stylish in a cream dress coat by Scandinavian fashion brand DAY Birger et Mikkelsen - an outfit she has worn on previous occasions
Tomorrow the Cambridges will watch the sport of goalball at the Olympic Park and track cycling, and later that day the Duchess will attend swimming races.
Kate will also undertake a solo engagement on Sunday watching the athletics at the Olympic Stadium.
Prince Harry will make his first public appearance since being photographed naked in a hotel suite when he cheers on Paralympic athletes on Monday.
He will watch swimmers in the aquatic centre and later chat to sportsmen and women in the official meeting place for the country's competitors - ParalympicsGB House.
Headlines were generated around the world when pictures of Harry frolicking in the nude with an unnamed naked woman, during a Las Vegas holiday, emerged on a celebrity gossip website last Wednesday.