150401-N-WA189-051 RIO DE JANEIRO, Brazil (March 31, 2015) Rear Adm. George Ballance, right, commander of U.S. Naval Forces Southern Command and U.S. 4th Fleet, and Brazilian navy Rear Adm. Renato Melo sign the memorandum of understanding for UNITAS, a multinational naval exercise beginning this November. (U.S. Navy Photo by Mass Communication Specialist 2nd Class Adam Henderson/Released)