Wangari Maathai smiles

Wangari Maathai, winner of the Nobel Peace Prize, smiles in this photo from the website of the Green Belt Movement, the organization she founded in Kenya. Wangari Maathai began promoting the planting of trees to reverse deforestation and provide firewood for African women in 1976. Nearly three decades later, in 2004, she was given the Nobel Prize for her work. She died of cancer in 2011.