President Barack Obama walks with Brazilian President Dilma Rousseff, second from right, during a visit to the Martin Luther King Jr. Memorial in Washington, D.C., on Monday. Evan Vucci/AP hide caption

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U.S. Defense Secretary Ash Carter, right, and Vietnam's Defense Minister Phung Quang Thanh review the guard of honour during a welcoming ceremony at the Defense Ministry in Hanoi, Vietnam, on June 1. The U.S., Russia, France, the U.K. and other countries are all jockeying to sell military equipment to Southeast Asian countries. Hoang Dinh Nam/Reuters/Landov hide caption

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The Polar Star completes ice drills in the Arctic in July 2013. Built in the 1970s and only meant to last 30 years, the vessel is the U.S. Coast Guard's only heavy icebreaker. U.S. Coast Guard/Reuters/Landov hide caption

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Canadian-born Omar Khadr is seen in a courtroom sketch during a 2010 hearing at the U.S. military prison at Guantanamo Bay, Cuba. He was moved to a Canadian prison in 2012. Janet Hamlin/AP hide caption

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An airport official walks past a military aircraft destroyed by Saudi-led airstrikes, at the Sanaa International airport in Yemen on Tuesday. Destroyed runways prevent aid from being delivered. Hani Mohammed/AP hide caption

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Helicopter belonging to the Netherlands participates in NATO's Dynamic Mongoose anti-submarine exercise in the North Sea, off the coast of Norway, on May 4, 2015. MARIT HOMMEDAL/AFP/Getty Images hide caption

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Baltimore City State's Attorney Marilyn J. Mosby announces that criminal charges will be filed against Baltimore police officers in the death of Freddie Gray in Baltimore on Friday. Gray died in police custody after being arrested on April 12. Andrew Burton/Getty Images hide caption

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September 13, 2009 photo of Andreas Lubitz, who is believed to have deliberately crashed Germanwings Flight 9525 into a mountain in southern France on March 24, 2015, killing all 150 people on board. Getty Images/Getty Images hide caption

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