More than 150 U.S. Marines with Black Sea Rotational Force await the closing remarks for Exercise Summer Shield at Adazi Military Base, Latvia, March 31. The U.S. Marines with Black Sea Rotational Force brought the largest amount of Marines to the annual exercise since Summer Shield began in 2004. The Marines conducted small-unit training and combined-arms live-fire exercises with their Allies from Latvia, Lithuania, Luxembourg, Canada, and Germany.