At the night club in Boston after a fire broke out when a busboy lit a single match to retrieve a light bulb that he had dropped on the floor.
In the ensuing panic, patrons swarmed toward the single exit from the building, a revolving door at the main entrance that soon became blocked by the crush of bodies attempting to flee the site. In terms of the mortality rate, the Cocoanut Grove fire was the worst nightclub fire in history, but it stands far from alone as an instance of the disas- trous influence of human emotion interacting with the physical layout of an environment and causing death.
Every year at the Hajj, a massive pilgrimage to Mecca involv- ing more than five million participants, several hundred people are crushed underfoot when the crowds, reacting in part to the high emotion of the event, challenge the limitations of the physical set- ting. Sporting events, street festivals, parades, and demonstrations sometimes similarly turn awry, causing human tragedy. Such instan- ces of death by crowding have generated a small industry in prevent- ive measures ranging from building codes that impose upper limits on occupancy and lower limits on exits to sophisticated modeling software in which movements of crowds of individuals can be pre- dicted in proposed designs before they are constructed. Nevertheless, despite such measures, the simple and important fact remains that the level of anxiety experienced by visitors to any built setting will influence their behavior both at the individual level and at the aggre- gate level of the crowd.