GREAT LAKES, Ill. (Feb. 2, 2021) Master-at-Arms 1st Class Alexa Burton, a member of the installation training team, monitors Master-at-Arms 3rd Class Devin Cervantes (right) in exercise play on the second day of Exercise Citadel Shield - Solid Curtain 2021. Exercise Citadel Shield - Solid Curtain 2021 is a two-part, anti-terrorism force protection exercise that is being conducted nationwide on Navy installations, Feb. 1-12. The annual exercise is not in response to any specific threat, but is used to evaluate the readiness of fleet and installation security programs. (U.S. Navy photo by John Sheppard)