U.S. Marines with Special Purpose Marine Air-Ground Task Force-Crisis Response-Africa form a wall of shields to protect a simulated U.S. Embassy during a riot-control exercise at the National Gendarmerie Training Center in St. Astier, France, May 13, 2016. The Marines trained alongside the French National Gendarmerie to operate through dense smoke and CS gas while maintaining tightly organized formations. - U.S. Marines with Special Purpose Marine Air-Ground Task Force-Crisis Response-Africa form a wall of shields to protect a simulated U.S. Embassy during a riot-control exercise at the National Gendarmerie Training Center in St. Astier, France, May 13, 2016. The Marines trained alongside the French National Gendarmerie to operate through dense smoke and CS gas while maintaining tightly organized formations.