Officer Obstacle A Marine navigates a water obstacle at the Officer Candidate School at Marine Corps Base Quantico, Va., June 14, 2017. Candidates train for three months to evaluate leadership, moral, mental and physical qualities required for commissioning as a Marine Corps officer. Marine Corps photo by Lance Cpl. Cristian L. Ricardoo SHARE: Download: Full Size (0.53 MB) Credit: Lance Cpl. Cristian Ricardo VIRIN: 170614-M-BP749-307C.JPG Photo Gallery