A Chicago police officer punches an anti-NATO protester who was hitting officers with a stick as the two groups clash at the end of their march at Cermak Road and Michigan Avenue on Sunday, May 20, 2012.
{"Image ImageDescription": "A Chicago police officer punches an anti-NATO protester who was hitting officers with a stick as the two groups clash at the end of their march at Cermak Road and Michigan Avenue on Sunday, May 20, 2012. (Brian Cassella/Chicago Tribune/Tribune News Service via Getty Images)", "Image Copyright": "2014 MCT"}