Marine Corps Sgt. Maj. Paul McKenna of North American Aerospace Defense Command and U.S. Northern Command surveils the rural, expansive U.S.-Mexico border area from a Black Hawk helicopter, Aug. 14, 2018. Command senior enlisted leaders, led by Army Command Sgt. Maj. John Wayne Troxell, senior enlisted advisor to the chairman of the Joint Chiefs of Staff, traveled the U.S.-Mexico border to learn about the threats and challenges that affect the nation stemming from drug trafficking, human trafficking and other cartels. DoD photo by Terri Moon Cronk