The tallest building in North America is officially going green, along with a few of its Windy City counterparts. At a green building expo in Chicago yesterday, former President Bill Clinton and eterna-Mayor Richard Daley announced a partnership to retrofit landmarks including the Sears Tower and the Merchandise Mart, the nation’s largest commercial center. Using features like wind turbines and green roofs, the endeavor will seek to save energy, fight climate change, and — perhaps most important — show other communities and countries around the world that environment and economy do mix. Green building and other climate fixes represent “a staggering economic opportunity,” Clinton said. “I think this is the greatest opportunity our country has had to generate prosperity since we mobilized for World War I.” Daley, who first took office in 1914, nodded sagely.

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