U.S. Marine Sgt. Andrew Mercer, a military policeman from Military Police Company B, Headquarters and Service Battalion, 4th Marine Logistics Group, and an Allentown, Pa. native, leads students during a crowd control practice at Barbados Defence Force Base Paragon, Christ Church, Barbados, June 18, 2012, for Exercise Tradewinds 2012. Tradewinds is a multinational, interagency exercise designed to develop and sustain relationships that improve the capacity of U.S., Canadian and 15 Caribbean partner nations security forces to counter transnational crime and provide humanitarian assistance and disaster relief.