A crewmember of the U.S. Coast Guard Maritime Security Response Team, based out of Chesapeake, Va., keeps watch on a passageway aboard the Icebreaker Mackinaw Maritime Museum, in Mackinaw City, Mich., during a hostile boarding and ship re-take training exercise held April 19, 2015, as part of Operation Arctic Eagle. Arctic Eagle is a joint service and international exercise, based on the U.S. and Denmark National Strategies for the Arctic, addressing the defense of critical infrastructure within the Arctic Circle. (U.S. Coast Guard photo by Petty Officer 3rd Class Christopher M. Yaw)