I saw/heard "In White America" at Augustana College in Sioux Falls, South Dakota, probably when I was about 15 years old. I was stunned. I really think I had no idea what all was going on in the world, much less the United States in the South. I learned much more from that play and some other books than I did in my American history classes.
Since that play was seared in my mind/memory, I also read books about Native Americans (I bury my Heart at Wounded Knee) and others.
Even books like "Centennial" and "Blood and Thunder" among others brought a bit more awakening to my world. However, it was "In White America" which I hope to reread.