Sometimes, a single decision can change the course of history. Join journalist and author Isabel Wilkerson as she tells the story of the Great Migration, the outpouring of six million African Americans from the Jim Crow South to cities in the North and West between World War I and the 1970s. This was the first time in American history that the lowest caste people signaled they had options and were willing to take them -- and the first time they had a chance to choose for themselves what they would do with their innate talents, Wilkerson explains. "These people, by their actions, were able to do what the powers that be, North and South, could not or would not do," she says. "They freed themselves."