One of the world's leading voices of conscience on the question of genocide and human rights is Samantha Power, who is now the U.S. Ambassador to the U.N.
She won a Pulitzer Prize a decade ago for her book, “‘A Problem from Hell’: America and the Age of Genocide.”
On Monday, she spoke with CNN’s Fred Pleitgen, in for Christiane Amanpour, from the Rwandan capital Kigali, where that country was marking 20 years since its horrific genocide.
Click above to see their conversation.