The two cities went head-to-head after Moscow, New York and Madrid dropped out in the first three rounds of voting.
London's plan focuses on the regeneration of a massive site in Stratford - in the east of London.
The new Olympic Park will be built within four London boroughs and will include an 80,000-seater stadium, an athletes' village and other key sporting venues.
The budget for the games has been set at £1.3bn with a further £8.3bn being spent on venues and transport.
The games will take place between July 27 and August 11 followed by the paralympics between August 31 and September 11.
There are expected to be eight million tickets available for the event priced between £15 and £55.
Existing venues such as Wimbledon and the Millennium Dome will be used. And the new Wembley, which is due to be completed next year, will host the football tournament.
And landmarks around the historic city will also be used as venues for major events.
Beach volleyball will be played in Horse Guards Parade, baseball and softball in Regent's Park and triathletes will cycle past the gates of Buckingham Palace.