A Nigerien soldier covers his face while taking a picture of a mass grave in the recently retaken town of Damasak, Nigeria, March 20, 2015. Soldiers from Niger and Chad who liberated the Nigerian town of Damasak from Boko Haram militants have discovered the bodies of at least 70 people, many with their throats slit, scattered under a bridge, a Reuters witness said. REUTERS/Emmanuel Braun