Right back to the bidding process, London 2012 organizers set themselves the target of holding a green Games.
It won the bid on a plan to hold an environmentally and economically sustainable games that would leave a legacy long after the closing ceremony.
A major part of the strategy came in the choice of the Olympic Park site at Stratford, a then industrial sprawl contaminated by more than a century of pollution and neglect.
London is also the first Games to set up an independent watchdog to monitor its progress.
The Olympic site will become the Queen Elizabeth Olympic Park after the Games with many of the venues and infrastructure giving way to even more parkland as well as businesses and entertainment areas.
Special coverage: 2012 London Olympic Games
Source: AP
Editor: Huan CAO
Voiceover: Chris Clark
Producer: Flora Yue