Russian President Dmitry Medvedev is greeted by Col. Clair Gilk, 316th Operations Group commander, on the flight line at Andrews AFB, Md., April 12, 2010. The national delegate landed at Andrews on his way to the Nuclear Security Summit hosted by President Barack Obama in Washington, D.C., April 12-13. The Air Force District of Washington facilitated and protected transiting heads-of-state while simultaneously working with all levels of government agencies to provide contingency support. (U.S. Air Force photo by Staff Sgt. Keyonna Fennell)