An eco-city or ecocity is "a human settlement modeled on the self-sustaining resilient structure and function of natural ecosystems", as defined by the Ecocity Builders (a non-profit organization started by Richard Register who first coined the term). Simply put, an eco-city is an ecologically healthy city. The World Bank defines eco-cities as "cities that enhance the well-being of citizens and society through integrated urban planning and management that harness the benefits of ecological systems and protect and nurture these assets for future generations". Although there is no universally accepted definition of an 'eco-city', among available definitions, there is some consensus on the basic features of an eco-city.