Yemenis walk past near oil tankers that were burnt during clashes between Shiite Houthi rebels and their opponents in the capital, Sanaa, in September. Saudi Arabia launched airstrikes this week to counter the Houthis' offensive. Mohammed Huwais/AFP/Getty Images hide caption

itoggle caption Mohammed Huwais/AFP/Getty Images

Israeli Prime Minister Benjamin Netanyahu speaks to supporters following the country's March 17 election. After a bruising campaign in which he faced considerable criticism, Netanyahu has taken a number of steps to try to ease tensions. Lior Mizrahi/Getty Images hide caption

itoggle caption Lior Mizrahi/Getty Images

Carlos Varela, a Cuban protest singer, poses for a picture at the bar of the historic Hotel Nacional in Havana. Eyder Peralta /NPR hide caption

itoggle caption Eyder Peralta /NPR

A Houthi Shiite fighter stands guard Thursday as people search for survivors under the rubble of houses destroyed by Saudi airstrikes near Sanaa Airport in Yemen. Hani Mohammed/AP hide caption

itoggle caption Hani Mohammed/AP

A Southwest Airlines pilot and co-pilot preparing for a flight from Dallas last year. In the wake of the Germanwings crash this week, many European airlines are rushing to adopt a two-person cockpit rule similar to the one already in place in the U.S. LM Otero/AP hide caption

itoggle caption LM Otero/AP

Police officers carry boxes outside a house in Montabaur, Germany, on Thursday in connection with the investigation into the Germanwings A320 crash. Fredrik von Erichsen /EPA /Landov hide caption

itoggle caption Fredrik von Erichsen /EPA /Landov

A man hammers a wall with elections posters at an open market in Kano, Nigeria, on Friday. The country is preparing for presidential elections on Saturday. President Goodluck Jonathan faces former military ruler Muhammadu Buhari and 13 other candidates in what is seen as the closest presidential race since the end of military rule in 1999. Goran Tomasevic/Reuters/Landov hide caption

itoggle caption Goran Tomasevic/Reuters/Landov