As the global population heads toward nine billion people by 2040, urban areas are facing increased pressure to provide services for ever-growing numbers of inhabitants. Cities create new ecosystems of human production and consumption that can provide great efficiencies in resource distribution (e.g., mass transit is far more energy efficient than individual transportationp every kilometer of pipe/rail/sewer serves a higher proportion of people than in the countryside). Hence, cities are not necessarily bad for the environmentp in fact, they could be ideal solutions for many of the challenges faced by our growing populations. We seek proposals from around the world that aim to test innovative approaches to issues surrounding the production or consumption of energy, food, infrastructure (including transportation or "green space"), and fresh water in and around cities.