Cities are now the economic powerhouses that drive most nations. We'll be asking whether it is it time for cities to be cut free from the rest of countries: is it time for urban devolution? We're in Brazil where delays to World Cup football stadiums and infrastructure projects have meant the reputation of some cities have taken a battering. Will Brazil's cities will be able to pull it out of the bag and recover their good names? And we've sent our South Korea correspondent Lucy Williamson to visit a brand new city in search of the elusive ingredients that create a truly great urban experience.