Gen. John F. Campbell, the top U.S. commander in Afghanistan, speaks during a ceremony in Kabul on Aug. 26. Campbell is overseeing the U.S. drawdown in the country after 13 years of war. Massoud Hossaini/AP hide caption

itoggle caption Massoud Hossaini/AP

Four Americans injured in Iraq and Afghanistan visit Kabul as part of Operation Proper Exit, a program designed for wounded warriors. From left, they are Staff Sgt. Ben Dellinger, Capt. Casey Wolfe, Capt. John Urquhart (who is hidden) and Sgt. James "Eddie" Wright. Sean Carberry/NPR hide caption

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U.S. Marines board a C-130 transport plane as they withdraw from Camp Leatherneck, their huge base in southern Afghanistan. This marked the biggest handover yet to the Afghan army, which is facing a tough fight with the Taliban in Helmand province and other parts of southern Afghanistan. Wakil Koshar/AFP/Getty Images hide caption

itoggle caption Wakil Koshar/AFP/Getty Images

U.K. armed forces and U.S. Marines have ended combat operations in Afghanistan. In a formal handover, British troops stood with peers from the U.S. Marine Corps and the Afghan National Security Forces as the Union Flag and Stars and Stripes were lowered for the last time at the Bastion-Leatherneck complex Sunday. Sergeant Obi Igbo, RLC/AP hide caption

itoggle caption Sergeant Obi Igbo, RLC/AP

This year, Lynsey Addario photographed 13-year-old Rahaf Yousef, a Syrian refugee, at her engagement party at a camp in Jordan. "Syrian refugees typically marry young," says Addario. "It's been exacerbated by the war. Families are scared something might happen to their daughter. They prefer to marry them earlier so they're under the protection of a husband." Lynsey Addario/Reportage by Getty Images hide caption

itoggle caption Lynsey Addario/Reportage by Getty Images

Bolivia is one of the poorest countries in the Western hemisphere, but its senior citizens all benefit from a guaranteed pension. Antonio Olmos/Courtesy of Age International hide caption

itoggle caption Antonio Olmos/Courtesy of Age International

Afghan National Security Adviser Mohammad Hanif Atmar (right) and U.S. Ambassador to Afghanistan James Cunningham exchange documents after signing the Bilateral Security Agreement, with Afghan President Ashraf Ghani (rear, left) and Chief Executive Abdullah Abdullah in the background. Jawad Jalali/EPA/Landov hide caption

itoggle caption Jawad Jalali/EPA/Landov

Ashraf Ghani (second from left) stands next to Afghanistan's Chief Executive Abdullah Abdullah (left) and two deputy officials as he takes the oath during the inauguration ceremony at the presidential palace in Kabul on Monday. Ahmad Massoud/Xinhua/Landov hide caption

itoggle caption Ahmad Massoud/Xinhua/Landov

Afghan presidential candidates Abdullah Abdullah, left, and Ashraf Ghani Ahmadzai shake hands after signing a power-sharing pact in Kabul Sunday. The first vote in the election was held in April; a runoff followed in June. Wakil Kohsar/AFP/Getty Images hide caption

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Abdullah Abullah (left) and Ashraf Ghani, shown here on August 8, have been contesting the results of Afghanistan's runoff presidential election for months. They are expected to sign a power-sharing deal on Sunday. Wakil Kohsar/AFP/Getty Images hide caption

itoggle caption Wakil Kohsar/AFP/Getty Images