How can the operation of cities with digitally networked infrastructures be ensured in extreme situations, crises and disasters? Digital technology is present in all important aspects of modern cities. Energy, nutrition, water, transport, health, finance and administration are all increasingly controlled and networked by information and communication technology. This offers huge benefits for living and working in cities, but also results in new dependencies on these technologies. Natural disasters, human or technological failure, crime and terror can threaten digital systems. The networking, which under normal circumstances contributes to new levels of efficiency, can in a worst case crisis scenario, result in the complete failure of multiple critical systems. At the same time, information and communication systems are extremely useful, especially in times of crisis, and play a decisive role in both triggering a fast response and in the ongoing handling of a crisis. The LOEWE Center emergenCITY is working on solutions that increase the safety and security of digital cities and their digital infrastructure, including in times of crises. The solution concept is interdisciplinary and includes modern information and communication technology, cyber-physical systems as well as the historical, legal, social, and construction aspects of crisis and disaster prevention. emergenCITY conducts research into resilience based approaches in particular. We do not know what the next crisis will be. Good preparation means the ability to react flexibly and, through resilient information and communication systems, to maintain the ability to act. This is the only way to achieve a rapid recovery to normality.