Caldera volcanic eruptions create geological hazards that affect many communities around the world. Geophysical, geochemical and remote sensing data have become essential for understanding the tectono-magmatic activity in modern active calderas and the complexity of their underlying systems. In addition, for calderas where geophysical and geochemical monitoring data are lacking, interdisciplinary studies of past caldera eruptions have improved understanding of the evolution of tectono-magmatic systems and allowed the scientific community to validate numerical models that can predict the potential for caldera-associated eruptions. Overall, the studies of volcanic calderas and the evolution of their magmatic systems provide insights for improving risk reduction and hazard management strategies in the communities surrounding them.