What dream might the writer have in mind given that he calls his poem "Harlem"?

The dream that Hughes refers to represents the hopes for
social equality with whites that African Americans had cherished for so long but that
always been frustrated. The opening question of the poem serves as a kind of
introduction to the entire volume where it was published Montage of a Dream
Deferred (1951). Framed by two questions that indicate the lack of social
certainties, the poem takes the reader through images indicating that the dream of equal
civil rights has decayed. The ending warns that a dream may explode, i. e. that African
Americans could react violently to the constant rejection of their demands. This
scenario implies that continuing to ignore the discrimination against African Americans
could hurt the entire American society and expose how little inclusive the
American Dream really was.