Heavy smoke rises from the Westgate Mall in Nairobi, Kenya, on Monday. The Somali militant group al-Shabab claimed responsibility for the attack. Jerome Delay/AP hide caption

itoggle caption Jerome Delay/AP

Somali women and children wait to get medicine in July 2008, from a clinic run by Doctors Without Borders about 20 miles south of Mogadishu. AFP/AFP/Getty Images hide caption

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Ali Maow Maalin said he avoided getting the smallpox vaccine as a young man because he was afraid of needles. He didn't want others to make the same mistake with polio. Courtesy of the World Health Organization hide caption

itoggle caption Courtesy of the World Health Organization

A Yemeni child receives a polio vaccine in the capital city of Sanaa. The Yemen government launched an immunization campaign last month in response to the polio outbreak in neighboring Somalia. Mohammed Huwais/AFP/Getty Images hide caption

itoggle caption Mohammed Huwais/AFP/Getty Images

Health workers vaccinate a boy against polio at a May immunization drive in Mogadishu, Somalia. Farah Abdi Warsameh/AP hide caption

itoggle caption Farah Abdi Warsameh/AP

An undated screen image of footage shot by Al-Kataib Media, showing Denis Allex, a French hostage allegedly held by Somali militants, who was reportedly killed during the failed rescue mission. MAXPPP/EPA /LANDOV hide caption

itoggle caption MAXPPP/EPA /LANDOV

In October, kidnapped French intelligence agent Denis Allex appeared in a video shot by his captors. In the video, Allex pleads for French President Francois Hollande to negotiate for his release. -/AFP/Getty Images hide caption

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Somali chef Ahmed Jama holds up freshly caught spiny lobsters he's about to cook in one of his restaurants in Mogadishu. John Burnett/NPR hide caption

itoggle caption John Burnett/NPR

Ambulances are parked outside the Mogadishu National Theatre on Wednesday after a suicide attack in the Somali capital. A young woman strapped with explosives blew herself up on at a ceremony in the Somali national theater attended by the prime minister and other officials. Abdurashid Abdulle/AFP/Getty Images hide caption

itoggle caption Abdurashid Abdulle/AFP/Getty Images