Thurgood Marshall changed American history by challenging it. In the first half of the twentieth century, African Americans were often treated as second-class citizens and subject to Jim Crow laws, which promoted both racism and segregation. This is the world that Marshall grew up in, and he became a lawyer to change it. As the head counsel for the National Association for the Advancement of Colored People (NAACP), he helped take the famous Brown v. Board of Education all the way to the U.S. Supreme Court. And in an outcome surprising even to him, the court unanimously ruled to end segregation in schools. Thurgood Marshall had become a hero.