Earlier this month, Mohammed bin Salman, Saudi Arabia's new deputy crown prince, met with Egyptian President Abdel Fattah el-Sissi in Cairo. Egyptian Presidency Handout/EPA /Landov hide caption

itoggle caption Egyptian Presidency Handout/EPA /Landov

Saudi Arabia's army fires artillery shells toward Houthi rebels along the Saudi border with Yemen on April 15. Outside Saudi Arabia, many are critical of the military campaign and question whether it will succeed, but it is popular inside the kingdom. STR /Reuters/Landov hide caption

itoggle caption STR /Reuters/Landov

The Migrant Offshore Aid Station (MOAS) carries out its first rescue in the Mediterranean in August 2014. The Malta-based private rescue service founded by a wealthy American and his Italian wife has rescued more than 3,000 migrants since its launch in August 2014. Barcroft Media /Landov hide caption

itoggle caption Barcroft Media /Landov

Survivors are escorted from the National Bardo Museum in Tunis on Wednesday. At least 20 foreign tourists were reportedly killed in the attack. Mohamed Messara/EPA/Landov hide caption

itoggle caption Mohamed Messara/EPA/Landov