If Man is looked at as a molecule, then forces analogous to temperature and pressure can shape Him into various phases. A small commune or tradition-bound village can be likened to a crystal: rigid, but stable and harmonious. Life in great urban centers is closer to a liquid: the particles stream and flow, creating turbulence and vortexes, but also capable of spreading wide and fast. What, then, is a crowd?
A crowd is like the superheated plasma in which atoms break down into component quarks to which the old rules no longer apply. Crowds are treated as localized epidemics of insanity; even a placid parade merits police on horseback. Perhaps it is some primordial instinct to return to the Collective, but people can quickly give up much autonomy and reason when in the crowd. No wonder, then, that some find large groups of people terrifying.
Agora is an art installation at the south end of Chicago’s Grant Park. Its 106 massive steel torsos mill about, loosely clustering together. A walk through this site captures that dread discussed above. Even non-agoraphobes can get a taste of the disorder if they lose themselves to reverie amongst these figures.