U.S. service members participate in the Wolf Pack’s 20 Year Anniversary 9/11 Memorial Ruck March at Kunsan Air Base, Republic of Korea, Sept. 10, 2021. Each ruck participant carried a badge in tribute to a first responder who lost their life at the World Trade Centers on Sept. 11, 2001. (U.S. Air Force photo by Staff Sgt. Gabrielle Spalding)