Normal, Alpha, Bravo, Charlie, and Delta. Each level represents a step up in tightening security as the threat increases.

Add Yahoo as a preferred source to see more of our stories on Google. Soldiers check the entrance to the NATO air base, a soldier in camouflage clothing is walking towards the air base. NATO had ...

Layered security models start from perimeter deterrence to high-security internal areas, ensuring comprehensive protection. Security entrances like full-height turnstiles, optical turnstiles, and ...

Soldiers check the entrance to the NATO air base in Geilenkirchen, Germany, Friday, Aug. 23, 2024, with the security alert state C sign on the left. (Christoph Reichwein/dpa via AP) Editor’s note: ...