International aid has poured into Afghanistan in recent years, but it is expected to fall sharply as NATO forces pull out. That will place great strains on the economy, and may lead skilled Afghans to leave if they can't find work. Here, street children in Kabul collect food from an aid group. Dar Yasin/AP hide caption

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A truck drives down a highway on Salang Pass in Afghanistan's Parwan province in December. The Salang Tunnel, which crosses under the pass, provides a vital link between Central Asia and northern Afghanistan to Kabul. Qais Usyan/AFP/Getty Images hide caption

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Responding to a Taliban attack, NATO Black Hawk helicopters fly over the Spozhmai Hotel on Lake Qargha outside Kabul. More than 20 people were killed before the Taliban fighters were shot dead. Massoud Hossaini/AFP/Getty Images hide caption

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Sgt. Michael Clark and his fiancee, Kaitlin Forant, hold their son, Michael Clark Jr. It took time for the 18-month-old to recognize his father after Clark's deployment. Tom Dreisbach/NPR hide caption

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The Natanz facility, shown here in a photo taken May 14, 2009, is about 150 miles from Tehran. AP/GeoEye Satellite Image/AP/GeoEye Satellite Image hide caption

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Sgt. Kyle Gonzales, a sniper with the 82nd Airborne, has a cigarette after a gun battle near the village of Babaker, Giro district, Ghazni province. The soldiers have engaged in gun battles every time they push into the hamlets north of their forward operating base. David Gilkey/NPR hide caption

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Marines with Echo Company of the Second Battalion, Ninth Marines out of Camp Lejeune, guide their M-ATV, a Mine Resistant Ambush Protected vehicle in to the district government compound in Marjah, Afghanistan. David Gilkey/NPR hide caption

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