190825-M-OP674-020 RIO DE JANERIO, Brazil (Aug. 25, 2019) U.S. Marines from Special Purpose Marine Air-Ground Task Force - Southern Command construct a terrain model of an island they're preparing to train on as 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. The task force’s mission is to work with partner nations to build security force capabilities in the Latin America and Caribbean region through recurrent training events. It is also trained and equipped to provide timely responses to natural disasters and other crisis situations in the region. (U.S. Marine Corps photo by Cpl. Amy Phan/Released)