Moreno kicks off a worldwide conversation, essential during a global health crisis, to analyze the complex and vibrant open-air laboratory that is the city, where our contradictions are expressed and changes in our lifestyles are tested. Petri dishes for most of the world's population, but also the major issues of human development - cultural, environmental, technological, and economic - today's urban spaces are today caught up in the challenges of the new century and require urgent reinvention.