What do you associate with the places Hughes describes in "The Negro Speaks of Rivers"?

As he was writing the poem, he symbolized the rivers he went to with the history and legacy of the Negro. Euphrates River represents the dawn of civilization, Congo - the region where the largest number of blacks were sold as slaves, Nile - importance of the ancient African civilizations, Mississippi - slavery and freedom.

All these mentioned rivers are significant in the history of the African Americans