Food companies can make safety evaluations of their products in secret without ever telling the Food and Drug Administration. Luciano Lozano/Ikon Images/Corbis hide caption

itoggle caption Luciano Lozano/Ikon Images/Corbis

Liberian workers dismantle shelters in an Ebola treatment center in the Paynes Ville neighborhood of Monrovia. Doctors Without Borders closed the center last month because it was no longer needed. Zoom Dosso/AFP/Getty Images hide caption

itoggle caption Zoom Dosso/AFP/Getty Images

Performance nutrition experts recommend stopping at all the hydration stations for a quick fill-up of a sports drink to replenish the glycogen that's being burned during a marathon. iStockphoto hide caption

itoggle caption iStockphoto

A woman cultivates seaweed off the coast of Madagascar to counter overfishing. She's working with Blue Ventures, a business that supports its conservation projects by giving ecotours. Courtesy of Skoll Foundation hide caption

itoggle caption Courtesy of Skoll Foundation

In the 1950s, the World Bank funded the creation of the world's largest man-made dam, the Kariba Dam, which sits on the border of Zimbabwe and Zambia. The construction of such dams can have dire consequences for poor people living near a river, an investigation found. Jekesai Njikizana/AFP/Getty Images hide caption

itoggle caption Jekesai Njikizana/AFP/Getty Images