U.S. Marine Corps Sgt. Kevin Manciavelez, an infantry squad leader with 2nd Battalion, 23rd Marines forward deployed with 4th Marine Regiment, 3d Marine Division as part of the Unit Deployment Program, commands fellow Marines during an assault of an underground tunnel with U.S. Army Soldiers with the 23rd Chemical Battalion during joint chemical, biological, radiological, and nuclear defense training during Korea Viper 25.4 at Camp Stanley, South Korea, May 20, 2025. Korea Viper is a recurring exercise series that demonstrates the Republic of Korea and U.S. Marine Corps' ability to respond decisively in the region as a singular, unified force while strengthening relationships and trust between the two allies. Manciavelez is a native of California. (U.S. Marine Corps photo by Lance Cpl. Tucker Mocan)