civil rights movement
The most interesting thing that happened in the 1960s and 1970s were cultural changes in the way that most people thought about their fellow citizens.
The Civil Rights Movement was one of these shifts that transformed the attitudes of the majority of American citizens and made them realise that ALL people were entitled to pursue the American dream.
People had been living a fairly conservative way in the late 1950s and early 1960s. Blacks didn't have legal equality. Many woman didn't work outside the home. Most people obeyed their parents and trusted the government.
By the early 1970s, none of that was true anymore. Americans wanted their troops to withdraw from the war in Vietnam. Fashion changed as well.
Before the late 1960s, African Americans had to live under a system of segregation. In some areas of the country, they were legally obliged to stay away from white suburbs, white schools, white shops, white restaurants, white jobs and white seats on busses.
After the early 1970s, blacks were (theoretically) allowed to go anywhere and do anything they wanted, even if it took them into proximity to white people. The country still has a long way to go in terms of providing REAL equality to all its citizens, but at least for now the laws can be enforced.