President Obama speaks during services honoring the life of the Rev. Clementa Pinckney on Friday. Carolyn Kaster/AP hide caption

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A police officer is silhouetted through the emergency room door at a public hospital in San Pedro Sula, Honduras. With 91 murders per 100,000 people, the Central American nation is often called the most violent in the world. The homicide rate is roughly 20 times that of the U.S. rate, according to a 2011 U.N. report. Esteban Felix/AP hide caption

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People sing as they take part in a prayer vigil at the site where two police officers were shot to death in the Brooklyn borough of New York this weekend. Carlow Allegri/Reuters /Landov hide caption

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In 2010, Omar Thornton killed eight colleagues in Manchester, Conn., before killing himself. Private employers used to create their own rules about guns on their property. But over the past five years, many states have adopted laws that allow employees to keep firearms in their vehicles at work. Douglas Healey/Getty Images hide caption

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Community members and students from Marysville-Pilchuck High School gather for a vigil at the Grove Church in Marysville, Wash., Friday night. Two students died in the violence, including the gunman. Several more were wounded. David Ryder/Getty Images hide caption

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Surrendered handguns are piled in a bin during a gun buyback event in Los Angeles on May 31, 2014. David McNew/Getty Images hide caption

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Fifth-graders from the Bradwell School of Excellence in Chicago's South Shore area wrote an op-ed piece for The Chicago Tribune this week, explaining how they see their neighborhood. Google hide caption

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Police cordon off the area around a shooting in Chicago Wednesday. The violence broke out down the street from where NPR's David Schaper was conducting an interview about urban renewal efforts. David Schaper /NPR hide caption

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A makeshift memorial sits in front of IV Deli Mart, where part of Friday night's mass shooting took place in the Isla Vista, Calif., community. The parents of Elliot Rodger, accused of killing six people, were reportedly rushing to try to stop their son when they heard about the violence. Chris Carlson/AP hide caption

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