She was the first swimmer in history to win back-to-back Olympic and world titles in the same event, the 800-meter freestyle (Olympics: 1988, 1992; world championships: 1991, 1994). Meet the exceptional ladies who dared to raise the subject of gender equality and other concerns. Their stories tell us much about where we have come from and where we might go next. These are the 10 greatest women swimmers of all time.