The original UPI photo that was published with the New York Times article.
An additional, unpublished UPI riot photo.
Another unpublished, “day after” UPI riot photo.
Here are a series of unpublished photos from the UPI and the Associated Press.
Cleaning up after the riot. Note the lone guardsman still standing watch on top of the Half Moon Bowling Alley.
According to the New York Time article at the top of this page, the riot was started by the Hells Angels. Below is an interesting 1969 article exploring the psyche of the Hells Angels.