ON OUR WATCH

The world vowed "never again" after the genocide in Rwanda and the atrocities in Srebrenica, Bosnia. Then came Darfur. Over the past four years, at least 200,000 people have been killed, 2.5 million driven from their homes, and mass rape has been used as a weapon in a brutal campaign supported by the Sudanese government. In On Our Watch, FRONTLINE asks why the United Nations and its members once again failed to stop the slaughter.