A NATO firefighter dons his gas mask during the NATO Firefighter Fundamentals Course at Ramstein Air Base, Germany, March 11, 2020. The mask protects firefighters from harmful gas expelled while extinguishing fires and provides oxygen to breathe. Firefighters from Bulgaria, Latvia, Lithuania and the Czech Republic came to Ramstein to receive certification on extracting pilots and extinguishing aircraft fires. (U.S. Air Force photo by Airman 1st Class Taylor D. Slater)