The Olympics are in full swing, with the world's attention on the playing fields and pools dotting the United Kingdom. But how about the venues themselves, how green are they? The London Organizing Committee planned the Games with a green tint, focusing on sustainable principles for everything from stadium construction, food service, and the use of public transportation. Plus, the large number of preexisting venues around the city (tennis at Wimbledon, for example) made some additional construction unnecessary.

Planning for Green - The Organizing Committee took the forward-thinking step of setting up the London Legacy Development Corporation three years ahead of the Games, which has focused on long-term uses of the Olympic venues after the torch is passed to Russia's winter Olympics. The Development Corporation's plans for housing and parks were developed with an eye to rebuilding parts of London, particularly East London. The Organizing Committee even took the extra step of working with the Independent Standards Organization to develop a global standard for sustainable event management, now known as ISO 20121:2012.

Green Building - Venues constructed for the games include a number of innovative green features. The roof of Olympic Stadium, for example, was constructed from unwanted gas pipes from the North Sea and over 40% of the concrete used for construction is made of recycled materials. While the question remains as to whether this much new construction can ever be considered truly sustainable when developed for a single mega-event, the Organizing Committee took great steps to reduce waste. Many Olympic venues that do not have long-term uses were built only to be used for the Games and will then be taken apart and their materials will be reused.

Looks like a tough act to follow for Sochi and Rio.