150527-N-TI693-042 PANAMA CITY, Fla. (May 27, 2015) Secretary of the Navy (SECNAV) Ray Mabus, right, listens as Cmdr. Hung Cao, commanding officer of Naval Diving and Salvage Training Center (NDSTC) explains the daily training regimen that the students go through. 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)