Nuclear Security Summit 2016 to kick off in Washington, D.C (11)

WASHINGTON D.C., March 30 -- A Secret Service policeman patrols inside the International Media Center at the Walter E. Washington Convention Center, in Washington, D.C., United States, March 30, 2016. The Nuclear Security Summit 2016 will be held here from March 31 to April 1. (Xinhua/Li Muzi)