Policy Commons: World Cities This link opens in a new windowWorld Cities preserves the full text of surveys, budgets, statistical records, case studies, planning documents, training manuals, policy guidelines, reports, and news from the world’s top 100 cities by population, capital cities with populations greater than 20,000 people, major cities in the Global South, and cities with particular research importance, such as those dealing with climate change, political instability, or rapid growth.