A Marine with 2nd Reconnaissance Battalion, 2nd Marine Division conducts a 500 meter underwater swim with fins and a snorkel at the Courthouse Bay Training Tank aboard Marine Corps Base Camp Lejeune, N.C., March 19. Approximately 20 Marines from 2nd Recon Bn. participated in a two week pre-dive course in which they conducted exercises that would ready them for Combatant Diver Course.