Mattis Greeting Defense Secretary Jim Mattis shakes hands with U.S. Ambassador to the United Kingdom Lewis Lukens at the U.S. Embassy in London, March 31, 2017. DoD photo by Army Sgt. Amber I. Smith SHARE IMAGE: Download Image: Full Size (1.47 MB) Tags: Travels , JIm Mattis, SecDef, Atlantic Resolve Photo By: Amber I. Smith VIRIN: 170331-D-SV709-008.JPG Photo Gallery