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After training, teachers and other staffers in South Dakota could choose to bring guns with them to school if their districts want to set up "sentinel" programs. Jim Urquhart /Reuters /Landov hide caption

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Jim Urquhart /Reuters /Landov

A drawing depicts the death of St. Valentine — one of them, anyway. The Romans executed two men by that name on Feb. 14 of different years in the 3rd century A.D. Hulton Archive/Getty Images hide caption

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Hulton Archive/Getty Images