A new traveling exhibition is attempting to bring attention the architectural/cultural phenomenon of urban “greening,” a philosophy which allows cities to build big skyscrapers and massive sports stadiums, so long as they “consume less energy, use renewable materials and resources, and uplift their surroundings and the spirits of those who work in them.” It’s an intriguing concept, but most American cities, even those which consider themselves to be on the cutting edge of both architecture and the movement towards making cities more inviting, haven’t even begun to explore the possibilities of building green.