From TED: Architect and designer William McDonough asks what our buildings and products would look like if designers took into account "All children, all species, for all time." A tireless proponent of absolute sustainability (with a deadpan sense of humor), he explains his philosophy of "cradle to cradle" design, which bridge the needs of ecology and economics. He also shares some of his most inspiring work, including the world's largest green roof (at the Ford plant in Dearborn, Michigan), and the entire sustainable cities he's designing in China.