150527-N-TI693-054 PANAMA CITY, Fla. (May 27, 2015) Secretary of the Navy (SECNAV) Ray Mabus looks into the MK 37 diving helmet as he prepares for a dive at the Naval Diving and Salvage Training Center (NDSTC). NDSTC is the largest diving training facility in the world and is home of the military diver. U.S. Navy photo by Mass Communication Specialist Fred Gray IV/Released)