Marine Recruits Marine Corps recruits participate in an obstacle course during the Crucible at Marine Corps Recruit Depot Parris Island, S.C., Jan. 24, 2020. The Crucible is a 54-hour field training exercise that presents continuous physical and mental challenges. SHARE: Download: Full Size (1.15 MB) Tags: Marine Corps Credit: Marine Corps Lance Cpl. Godfrey Ampong VIRIN: 200127-M-GA002-1003B.JPG Photo Gallery