On May 16, active-duty and veteran U.S. Marines from units stationed around the globe gathered in Camp Pendleton, California, to participate in the annual Recon Challenge.

The Recon Challenge is an endurance event that takes participants through numerous tests inspired by the Reconnaissance Marine training and operational history. There is, for example, a grueling 30-mile ruck made while carrying more than 50 pounds of gear, a one-mile swim, an obstacle course, and marksmanship tests.

Marines formed up and competed in two-man teams, with each team representing a fallen Marine by wearing his name on their rucksacks. Upon crossing the finishing line, the teams hung their fallen brother’s dog tag on a makeshift combat cross as a final testament of remembrance.

This year’s challenge, which was the 11th, had 22 regular teams and one unique team comprised of 13 men.