Sergio Vieira de Mello was the man in charge of the United Nations mission in Iraq in 2003. He was killed along with 22 others when a truck bomb exploded at UN headquarters in Baghdad.
Samantha Power spent four years of her life researching the life and tragic death of Sergio Vieira de Mello. The Brazilian diplomat spent 35 years with the UN, trying to patch up countries in crisis.
Listen to the interview with Samantha Power