190825-M-OP674-068 RIO DE JANERIO, Brazil (Aug. 25, 2019) U.S. Marines, Brazilian marines and Colombian marines conduct a rehearsal of concept (ROC) drill during UNITAS LX at Ilha da Marambia Aug. 25, 2019. Service members use ROC drills to plan movements for complicated training exercise or operations. UNITAS is the world's longest-running, annual exercise and brings together multinational forces from 11 countries to include Brazil, Colombia, Peru, Chile, Argentina, Ecuador, Panama, Paraguay, Mexico, Great Britain and the United States. The exercise focuses in strengthening the existing regional partnerships and encourages establishing new relationships through the exchange of maritime mission-focused knowledge and expertise during multinational training operations. (U.S. Marine Corps photo by Cpl. Amy Phan/Released)