A Royal Marine Commando pulls security during Angel Thunder 17 in Florence, Ariz, May 11, 2017. Angel Thunder is a two-week, Air Combat Command-sponsored, joint certified and accredited personnel recovery exercise focused on search and rescue. The exercise is designed to provide provide training for personnel recovery assets using a variety of scenarios to simulate deployment conditions and contingencies. (U.S. Air Force photo/Staff Sgt. Sean Martin)