This is unedited video from a clash between protesters and police that occurred at 8:30 p.m. on Sunday.
It happened around the time the offshoot protest route that marched to the southern gates around McCormick Place (which was being guarded by guys in full riot gear and LRADs), marched back north and met with the other group around Michigan and Jackson. An LRAD is a long range acoustic device, or sound cannon.
It seems that someone was messing with a cops bike and everything just sort of went wild after that. It was impossible to tell what was going on aside from threatening night sticks and people half-running into each other. Then the rally circled the blocks a few times, finally settling on the Art Institute (Michele Obama was hosting a dinner for NATO spouses.
The trouble starts about 1 min. into the video, and at about 4 mins. a bloody protester named Harrison Shultz describes how he was hit from behind by police “two or three times.”