Great Migration (second) of Southern African-Americans to Northern cities begins.

Some six million African-Americans move from the South to cities in the North, Midwest, and East in what Nicholas Lemann later calls the largest demographic shift of any ethnic group in U.S. history. The shift is attributed to the invention of the mechanical cotton picker, which leads to a decrease in the need for manual agrarian labor. Between 1940 and 1960, Boston’s black population grows by 240% (from 23,679 to 63,165).