‘Running of the bulls’ festival crowds move like charged particles

People in a very dense crowd move in small circular “orbits”, like charged particles moving in a magnetic field. The unexpected discovery may help lead to improved mathematical descriptions of dense crowds, which could help us better understand why crowds sometimes move in a way that can lead to people being injured.

Denis Bartolo at ENS de Lyon in France and his colleagues studied videos of the dense crowds that form at the opening of the…