NORFOLK (Sept. 11, 2021) Flags fly at half mast in front of Headquarters Supreme Allied Command Transformation on Sept. 11, 2021. Allied Command Transformation is NATO's warfare development command located in North America, dedicated to preserving the peace, security, and territorial integrity of Alliance members by leading the warfare development of military structures, forces, and doctrines. (U.S. Navy photo by Mass Communication Specialist 2nd Class Benjamin Waddell)