Firefighters and security forces participate in a 9/11 memorial walk

U.S. Air Force fire department and security forces members participate in an evening memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force Senior Airmen, Cayden Saurbek, left, and John Hodgkind, left center, firefighters assigned to the 379th Expeditionary Civil Engineering Squadron, join Master Sgt. Jason Garrett, holding the flag, security forces member and Capt. Roy Blackledge, right, operations support officer assigned to the 379th Expeditionary Security Forces Squadron, to participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force fire department and security forces members participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force Staff Sgt. Austin Aldrich, firefighter assigned to the 379th Expeditionary Civil Engineering Squadron, carries a U.S. flag during an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force firefighters assigned to the 379th Expeditionary Civil Engineering Squadron carry fire hoses and wear self-contained breathing apparatus as they participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001.. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force Senior Airmen Mario Romero, left, and Daniel Martinez, firefighters assigned to the 379th Expeditionary Civil Engineering Squadron, participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force fire department and security forces members participate in an evening memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force firefighters assigned to the 379th Expeditionary Civil Engineering Squadron wear self-contained breathing apparatus as they participate in an evening memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force Staff Sgt. Allen Patterson, left, and Tech. Sgt. Adam Murray, firefighters assigned to the 379th Expeditionary Civil Engineering Squadron, participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force Senior Airmen Tyler Fisher, left, and Creed Heidkamp, firefighters assigned to the 379th Expeditionary Civil Engineering Squadron, participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force Senior Airmen Mario Jaquez, left, and Matthew Brooks, firefighters assigned to the 379th Expeditionary Civil Engineering Squadron, participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force fire department and security forces members participate in an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)

U.S. Air Force fire department and security forces gather for a group photograph after completing an evening 9/11 memorial walk at Al Udeid Air Base, Qatar, Sept. 11, 2017. Traditionally, on the anniversary of the terrorist attacks, firefighters climb 343 stairs in honor of the fire and emergency services members that lost their lives on Sept. 11, 2001. Firefighters and security forces here at Al Udeid Air Base walked 3.43 miles to honor those who lost their lives on Sept. 11, 2001. (U.S. Air National Guard photo by Tech. Sgt. Bradly A. Schneider/Released)