Redlining has been a widespread practice into the 1980s (at least) in the United States. How has this been exposed, and what steps have been taken to remedy the situation?

The Fair Housing Act of 1968 prohibited the practice generally, and the Community Reinvestment Act of 1977 was intended to put an end to all redlining practices. Can you tell a little more about what makes you think it was "a widespread practice into the 1980s?"