Bells have rung out across the country to mark the official start of the 2012 Olympics.

For three minutes church bells chimed, and even Big Ben 'bonged', to celebrate the first day of the London Games.

It's thought tonight's Opening Ceremony will attract ONE BILLION viewers worldwide.

The man who designed the venue - chief architect Rod Sheard - says tonight's atmosphere will be something special:

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B/A: We still don't know who will light the flame in the stadium, but Roger Bannister - the first man to run the four minute mile - is the favourite.