Demolition work has begun on the Olympic Park, the venue which will form the heart of the 2012 Games in London.
London 2012 chairman Lord Coe was on hand as the work began
A disused sports hall at Eton Manor, in the north of the 500-acre site, was the first building to be knocked down.
The Eton Manor site will host Paralympic tennis and archery and will be a training area during the Olympics.
London 2012 chairman Sebastian Coe said: "This is another important landmark for us on the road to delivering a memorable Olympic Games."
The first UK athletics meeting after World War II was held at Eton Manor and part of the running track used in the 1948 Olympics is buried underneath the site.
Eton Manor Clubs moved out of the area over 25 years ago and the site is now overgrown and in a state of disrepair.
Olympics Minister Tessa Jowell said: "The beginning of the demolition on
site underlines the excellent progress we have made to date."