Mattis Departure Defense Secretary James N. Mattis, left, walks with Ambassador William J. Burns after a fireside chat at the Carnegie Endowment for International Peace, Washington, D.C., Jan. 29, 2018. DoD photo by Tech Sgt. Vernon Young Jr. SHARE IMAGE: Download Image: Full Size (2.71 MB) Photo By: Tech Sgt. Vernon Young Jr. VIRIN: 180130-D-HG842-0003.JPG Photo Gallery