Cities are hubs for ideas, commerce, culture, science, productivity, social development and much more. At their best, cities have enabled people to advance socially and economically. However, many challenges must be addressed to ensure that cities continue to create jobs and prosperity, without putting a strain on land and resources. Common urban challenges include congestion, a lack of funds to provide basic services, a shortage of adequate housing and deteriorating infrastructure. These challenges can be overcome in ways that allow cities to continue to thrive and grow, while improving resource use and reducing pollution and poverty. The desirable future is one in which cities provide access to basic services, energy, housing, transportation and more opportunities for all.