The Black Panthers
Behind today's door - Black Panther - erm, which actually has very little to do with today's topic, unless you think about the changing attitudes to Black people in American culture from the 1970s.
How did the atmosphere of Civil Rights change by the 1970s?
This History Chanel page and its videos are a very interesting overview. What else should go in an "Explain why ..." answer about this topic? Malcolm X, the Kerner Report, the Watts riots ... information of your own ...