CHICAGO WALL U.S. Defense Secretary Leon E. Panetta and Secretary of State Hillary Rodham Clinton walk by the wall dedicated to the 175th birthday of Chicago at the NATO "jumbo" ministerial at NATO headquarters in Brussels, April 18, 2012. Panetta was in Brussels to meet with various NATO members and NATO defense and foreign affairs ministers. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 806406-B-MUF57-265.jpg Photo Gallery