Southern Seas 2015 The USS George Washington steams in formation with Mexico, Chile and Colombia during UNITAS 2015 PHOTOEX, off the coast of Chile, Oct. 17, 2015. This is the 56th iteration of UNITAS, the U.S. Navy's longest running annual multinational maritime exercise, and a part of Southern Seas 2015. U.S. Navy photo by Petty Officer 2nd Class Adam Henderson SHARE: Download: Full Size (1.1 MB) Credit: Petty Officer 2nd Class Adam Henderson VIRIN: 151017-N-TE668-520.JPG Photo Gallery