The world invoked its vow "Never Again" after the genocide in Rwanda and the atrocities in Srebrenica. 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 rapes have once more been used as a weapon of war in a brutal campaign - supported by the Sudanese government - against civilians in Darfur. Frontline asks why the international community and the United Nations once again failed to stop the slaughter.

As the United Nations was proving ineffective in stopping the killing, a grassroots movement to save Darfur was building. Frontline travels with actress and UNICEF goodwill ambassador Mia Farrow to the refugee camps in eastern Chad, her seventh trip to the region to document and raise awareness of the unfolding atrocities.

Tuesday, 6/10/08 from 10-11 p.m. ET