The stirring 72-minute oration, given without notes, came at a seminal moment in the modern civil rights movement. King had just inspired � and in some cases terrified � the nation with his victory in the Montgomery bus boycotts. Fear at the time was so great that no church, black or white, in Greensboro, N.C., was willing to host the young minister.

But when a historically black college for women offered its chapel, more than 1,500 people came and the crowd overflowed into the basement.