A trader on the floor of the New York Stock Exchange looks at stocks during the final minutes of trading on May 6. The Dow fell more than 600 points in a few minutes in what became known as the "flash crash." Timothy A. Clary/AFP/Getty Images hide caption

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Soldiers from Niger patrol the road between Agadez and Arlit in September. Issouf Sanogo/Getty Images hide caption

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George Guarch greets children at the Miami airport in the early 1960s. His daughter, Lynn, says George would carry the youngest children off the planes. Lynn Guarch Pardo hide caption

itoggle caption Lynn Guarch Pardo

The number of people killed on American roads has fallen by more than 20 percent in recent years, according to a new study. But motorcycle deaths are up. That may be because older drivers are buying motorcycles. iStockphoto.com hide caption

itoggle caption iStockphoto.com