White Flight.

Race riots more violent than any in the history of the United States shocked Americans during the decade; in every region of the country major cities threatened to go up in flames. Since the years immediately following World War II, middle-class white Americans had been leaving the city for nearby suburbs, and businesses that had once provided jobs and a tax base for the city soon followed. Increasingly, downtown — the inner city — was home to lower-income minorities, many of them southern blacks who came in large numbers to the North to find work. The decay of the inner cities perpetuated itself: economically disadvantaged Americans had to live in the low-rent housing such areas offered, which in turn caused more white flight to the suburbs for the Americans that could afford it and the businesses they patronized.

Powderkegs.

As the decade progressed...