Emergence of collective oscillations in massive human crowds

Dense crowds form some of the most dangerous environments in modern society1. Dangers arise from uncontrolled collective motions, leading to compression against walls, suffocation and fatalities2–4. Our current understanding of crowd dynamics primarily relies on heuristic collision models, which effectively capture the behaviour observed in small groups of people5,6. However, the emergent dynamics of dense crowds, composed of thousands of individuals, remains a formidable many-body problem lacking quantitative experimental characterization and explanations rooted in first principles. Here we analyse the dynamics of thousands of densely packed individuals at the San Fermín festival (Spain) and infer a physical…