The environmental and urban challenges outlined in this report require urgent and sustained attention from everyone involved in building or managing cities. To achieve Sustainable Development Goal (SDG) 11, we must make cities and human settlements inclusive, safe, resilient and environmentally sustainable. UNEP, UN-Habitat, the GEO for Cities Advisory Committee, its co-chairs and the expert authors hope that this report will lead to the urgent action needed for cities to become the beacons of environmental excellence that help their citizens lead productive, prosperous and equitable lives. Enjoy and take action!