Life on earth will be transformed by two changes currently under way: migration to cities and the fourth industrial revolution, involving AI, blockchain, IoT, robots, additive printing, virtual reality, biotechnologies, and new approaches to energy. In the coming revolution, agility is the watchword. Cities must adopt it and learn to “move quickly and easily”, if they are to provide good living conditions to their inhabitants, says the World Economic Forum. The WEF’s white paper, entitled “Agile Cities Preparing for the Fourth Industrial Revolution”, offers urban decision makers a framework, a method, and a set of indicators to ensure a good level of agility in city buildings, land, security, energy, mobility, education, and governance, in addition to the digital core with the new technologies.