Sailors from the U.S. Navy the Royal Australian navy dive into the pool to start the second heat of the 200 meter freestyle relay during a Rim of the Pacific Exercise (RIMPAC) international swim meet July 6, 2012, in Scott Pool at Joint Base Pearl Harbor-Hickam, Hawaii. More than 100 sailors from multiple nations gathered at Scott Pool to compete in a friendly swim meet and get to know each other prior to the start of the operational portion of RIMPAC 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.