Secretary Arrival Air Force Gen. Lori Robinson, commander of U.S. Northern Command, greets Defense Secretary Jim Mattis at Peterson Air Force Base, Colo., Nov. 16, 2017. DoD photo by Army Sgt. Amber I. Smith SHARE IMAGE: Download Image: Full Size (1.29 MB) Tags: Travels , JIm Mattis, SecDef, Northcom, Northern Command Photo By: Sgt. Amber I. Smith VIRIN: 171116-D-SV709-0041.JPG Photo Gallery