Nichelle Nichols caused a sensation in the 1960s for her role as Lieutenant Uhura in the classic television series, "Star Trek." It was one of the first times a black woman was cast as a main character in a major television show. But Nichols almost quit the show to pursue other dreams. She talks to host Michel Martin about her character's importance during the civil rights movement, and how Martin Luther King Junior convinced her to stay on "Star Trek".