River Crossing Marine Corps officer candidates navigate through the combat course during Officer Candidates School at Marine Corps Base Quantico, Va., July 29, 2021. The course simulates an environment that may be encountered on the battlefield. SHARE IMAGE: Download Image: Full Size (0.94 MB) Tags: marine corps Photo By: Tia Dufour, Marine Corps VIRIN: 210729-M-KS211-0662.JPG Photo Gallery