A Bulgarian border policeman stands near a barbed wire wall on the border with Turkey in July 2014. Experts believe that about two-thirds of the heroin that enters Europe comes through Bulgaria, and that a third of that moves on to the United States. Dimitar Dilkoff/AFP/Getty Images hide caption

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At Harmanli Camp in Bulgaria, hundred of asylum seekers — mostly from Syria and Afghanistan — live in reconfigured shipping containers and decommissioned military schools. The poor country is ill-equipped to deal with the influx of refugees from Syria. Jodi Hilton for NPR hide caption

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Keith Vaz, a British member of Parliament and chairman of the home affairs select committee (left), greets arrivals at Luton Airport, including Victor Spirescu (right) on Wednesday. The first Romanians and Bulgarians with unrestricted access to the U.K. labor market have begun to arrive despite last-ditch efforts to prevent a feared wave of fresh immigration. Jennifer Cockerell/PA Photos/Landov hide caption

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A chocolate cake is shaped like Europe, with new EU members Romania and Bulgaria (far right), at a welcoming ceremony for their entry into the bloc on Dec. 14, 2006. Curbs on the movement of citizens of the two countries end on Jan. 1, raising fears in Western Europe of an influx of Bulgarian and Romanian workers. Thierry Charlier/AP hide caption

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A screen grab from the surveillance video showing the man who it's suspected set off a bomb aboard a bus full of Israeli tourists in Burgas, Bulgaria. BGNES.com hide caption

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