ARRIVAL GREETINGS U.S. Defense Secretary Robert M. Gates, right, and Navy Adm. Mike Mullen, back right, chairman of the Joint Chiefs of Staff, exchange greetings with U.S. Ambassador to Mexico Carlos Pascual and Mexican officials after landing in Mexico City, March 22, 2010. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 776757-S-MJI31-512.jpg Photo Gallery