Pandemics of influenza, cholera, and plague are part of global history. Regional epidemics and pandemics of infectious diseases, primarily influenza A, continue to cause significant morbidity and mortality while remaining unpredictable in nature. Sudden-onset disasters such as earthquakes and floods occur with little warning. The consequences of climate change and environmental degradation can only be expected to increase the incidence of some infectious diseases and weather-related crises, adding to the unpredictability of such events. Health leaders, both in public health and healthcare, need to understand the international context and how coordination and response across or within jurisdictions will improve the likelihood of successful management of challenges. Public health emergencies respect no borders or political structures. The ability of institutions to adapt quickly can make a difference in health outcomes and a community's trust in those institutions.