GREAT LAKES, Ill. (Feb 2, 2021) Officer Matthew Milby, Naval Station Great Lakes Police, simulates hostage negotiations as part of Exercise Citadel Shield-Solid Curtain 2021. Exercise Citadel Shield-Solid Curtain 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 a response to any specific threat, but used to evaluate the readiness of fleet and installation security programs. (U.S. Navy photo by Mass Communication Specialist 2nd Class Brigitte Johnston)