Sean Morey, then with the Arizona Cardinals, celebrates after blocking a punt against the Seattle Seahawks in 2007. Morey, who suffers from post-concussion syndrome, retired from the NFL in 2010 on the advice of doctors. Stephen Dunn/Getty Images hide caption

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Janet Yellen smiles as President Obama announces her nomination for Federal Reserve chairwoman on Oct. 9. Jewel Samad/AFP/Getty Images hide caption

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Cannonball jellyfish soak up the sun on a South Carolina beach. Fishermen are now pursuing the pest that used to clog their shrimping nets. Courtesy of Steven Giese hide caption

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Linda Door protested outside the U.S. Supreme Court as it began hearing arguments on the constitutionality of the Affordable Care Act in March 2012. Carolyn Kaster/AP hide caption

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Speaker of the House John Boehner (right) speaks during the leadership press conference at the House Republican Issues Conference in Cambridge, Md., on Thursday. Friday's press conference, on the last day of the retreat, was canceled. JIm Watson /AFP/Getty Images hide caption

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A protest of the Keystone XL pipeline last March along its proposed route near Bradshaw, Nebraska. NH/AP hide caption

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Performers get ready before the start of a Chinese New Year parade in Hong Kong on Jan. 31. Philippe Lopez/AFP/Getty Images hide caption

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Gund Kwok troupe member Heang Ly takes a break next to her lion costume during a rehearsal in Boston's Chinatown. Hansi Lo Wang/NPR hide caption

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