Crucible Concentration Marine Corps recruit Colin G. VanZalen participates in the final challenge of recruit training, known as the Crucible, at Marine Corps Recruit Depot Parris Island, S.C., Nov. 22, 2019. SHARE IMAGE: Download Image: Full Size (0.78 MB) Tags: Marine Corps Photo By: Marine Corps Lance Cpl. Samuel Fletcher VIRIN: 191122-M-LS844-003C.JPG Photo Gallery