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Anti-NATO protesters fight with Chicago mounted police during an unpermitted march through Chicago streets. This was the sixth day of protests prior to the NATO Summit which runs May 20-21.
Eric Thayer / Reuters
Demonstrators clash with law enforcement officers during a protest.
Scott Olson / Getty Images
Demonstrators try to break through police lines as they march through the downtown streets of Chicago, Ill., May 19.
Three men were charged with conspiring to commit acts of terrorism at high-profile locations in Illinois ahead of the NATO summit. NBC's Kristen Welker reports.