A Republic of Korea Marine gets in position to provide security during a combined arms live-fire exercise as part of exercise Cobra Gold in Training Center Ban Chan Krem, Kingdom of Thailand, Feb. 21. Cobra Gold, in its 33rd iteration, demonstrates Kingdom of Thailand, U.S. and other participating nation commitment to regional partnership, prosperity and security in the Asia-Pacific region. The CALFEX is a field exercise which consisted of Royal Thai, Republic of Korea, and U.S. Marine infantry, mechanized infantry, and air assests to demonstrate unique capabilities of a multinational force. - A Republic of Korea Marine gets in position to provide security during a combined arms live-fire exercise as part of exercise Cobra Gold in Training Center Ban Chan Krem, Kingdom of Thailand, Feb. 21. Cobra Gold, in its 33rd iteration, demonstrates Kingdom of Thailand, U.S. and other participating nation commitment to regional partnership, prosperity and security in the Asia-Pacific region. The CALFEX is a field exercise which consisted of Royal Thai, Republic of Korea, and U.S. Marine infantry, mechanized infantry, and air assests to demonstrate unique capabilities of a multinational force.