A flint-knapper makes sharp stone flakes by striking a flint "core" with a hammerstone. Human Origins Initiative hide caption

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Feet On The Ground: Barefoot runners tend to land on the balls of their feet rather than on their heels the way most shoe-runners do. Rick Roeber went shoeless in 2003 and has clocked more than 13,000 barefoot miles since. Charlie Riedel/AP hide caption

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Anthropologist Brian Richmond is trying to determine what the footprints of modern humans can tell us about how we evolved. NPR hide caption

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The Leviathan melvillei attacks a medium-size baleen whale in this artist's rendition. C. Letenneur/MNHN hide caption

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Icebergs float in a bay off Ammassalik Island, Greenland. John McConnico/AP hide caption

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A worker drives an electric cart past air monitoring equipment in a storage room of the Waste Isolation Pilot Plant in Carlsbad, N.M. HO/AP hide caption

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Madagascar is a hot spot of extinctions, and members of the Chamaeleonidae family are currently going extinct. Ignacio De la Riva hide caption

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The U.S. Department of Energy spends $235 million to run the Waste Isolation Pilot Plant in Carlsbad, N.M. And that investment means jobs. Department of Energy hide caption

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An offshore oil rig is seen in the Catalina Channel near Long Beach, Calif., in 2008. On Monday, Gov. Arnold Schwarzenegger withdrew his support for a controversial new offshore oil drilling project off the Santa Barbara coast. David McNew/Getty Images hide caption

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