Wangar Maathal, the first African woman to win the Nobel Peace Prize, died of cancer Sunday at the age of 71. Maathal was given the award in 2004 for her work championing conservation, women’s rights, and better government. The founder of the Green Belt Movement, she first earned international attention the 1980s and '90s when she protested forest clearance in Kenya. She was arrested several times before becoming an M.P. in 2002.