U.S. Marines from the 3d Reconnaissance Battalion, part of the 3d Marine Division, conducted a patrol through an underground tunnel as part of the Korean Marine Exercise Program 25.1 at Camp Stanley, South Korea, on March 10, 2025. The Korean Marine Exercise Program 25.1 is a semi‑annual training event that brings together Republic of Korea Marine Corps and United States Marine Corps units to improve combined capabilities for deterrence and regional peace. The exercise includes a variety of tactical scenarios designed to test interoperability and readiness. The patrol shown in the image was captured by Lance Cpl. Kendrick Jackson of the United States Marine Corps. The continued execution of joint exercises reflects sustained cooperation between the two militaries, while the strategic impact of these drills on long‑term security remains under evaluation.