160405-N-TC720-082 BALTIC SEA (April 5, 2016) - USS Donald Cook (DDG 75) underway in the Baltic Sea April 5, 2016. Donald Cook, an Arleigh Burke-class guided-missile destroyer, forward deployed to Rota, Spain is conducting a routine patrol in the U.S. 6th Fleet area of operations in support of U.S. national security interests in Europe. (U.S. Navy photo by Mass Communication Specialist 2nd Class Mat Murch/Released)