The architecture firm Adrian Smith + Gordon Gill are working on a massive plan to "decarbonize" Chicago's Loop. The project incorporates a halt in new building; a retrofit of half of the area's existing structures; an effort to bring residences into old office buildings; and plans for better transportation, water management, and waste collection.The plan would, they say, reduce the city's energy use by 30 percent by 2020. You can check out more images and download the project .pdf here.Via Inhabitat.