Climate change, resource scarcity, and environmental degradation demand a paradigm shift in urban development. Currently, too many of our cities exacerbate these problems: they pollute, consume, and process resources in ways that negatively impact our natural world. Cities of the future must make nature their model, instituting circular metabolic processes that mimic, embrace, and enhance nature. In other words, a city must be a regenerative city or, as some say, an “ecopolis.”