U.S. Navy Senior Chief Conor Mcarty from Explosive Ordnance Disposal Unit 11 checks over his head gear prior to conducting fast rope training from a U.S. Navy MH-60S Nighthawk helicopter July 16, 2012, at Marine Corps Base Hawaii Kaneohe Bay during Rim of the Pacific Exercise 2012. Twenty-two nations, more than 40 ships and submarines, more than 200 aircraft and 25,000 personnel are participating in RIMPAC exercise from June 29 to Aug. 3, in and around the Hawaiian islands. The world's largest international maritime exercise, RIMPAC provides a unique training opportunity that helps participants foster and sustain the cooperative relationships that are critical to ensuring the safety of sea lanes and security on the worlds oceans. RIMPAC 2012 is the 23rd exercise in the series that began in 1971.