Whether to demonstrate military might, to advertise public events and holidays, or simply to entertain, parades traditionally have been part of the community experience, probably since human beings first gathered together in a social order; as far back as 3000 B.C.E., there are records of religious processions and parades. Whether it is a New York ticker tape parade or a ragtag local procession, a parade is a kind of social narrative, as symbols and tableaux approach and pass by, telling cheering spectators a sort of story about their society.

The first public parades were likely military or political in origin, as armies and rulers found that a huge demonstration of power was an effective way both to intimidate opposition and to muster support. Patriotism, that nationalistic pride so important to those who rule nations and those who make war, is still an important product of military and...