Secret Service agents patrol the day before the NATO Summit begins in Chicago

 
Secret Service agents patrol the day before the NATO Summit begins in Chicago
U.S. Secret Service agents patrol behind a security fence that marks the "Red Zone" area surrounding McCormick Place, the site of the NATO Summit, in Chicago May 19, 2012. The Summit runs May 20-21. REUTERS/Frank Polich (UNITED STATES - Tags: POLITICS)