Russian President Vladimir Putin (right) listens to French President Francois Hollande as they leave their news conference in Moscow on Thursday. Alexander Zemlianichenko/AP hide caption

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Joel Touitou Laloux's family owned Paris' Bataclan theater from 1976 until last year, when the performance hall was sold and he retired to Israel. He's shown here on Nov. 18 at his home in the Mediterranean coastal city of Ashdod in southern Israel. Jack Guez/AFP/Getty Images hide caption

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The closing ceremony of the Second Vatican Council in St. Peter Square on Dec. 9, 1965. Forty bishops pledged to forsake worldly goods, but the agreement was largely ignored. Pope Francis' emphasis on helping the poor has revived talk about the Pact of the Catacombs. Keystone-France/Gamma-Keystone via Getty Images hide caption

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Army soldiers and police patrol a street in the center of Brussels on Wednesday. Students are returning to class after a shutdown over fears that a series of simultaneous attacks could be launched around the Belgian capital. Geert Vanden Wijngaert/AP hide caption

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