A documentary on late 70's New York gangs, directed by Gary Weis, focusing on the Savage Nomads and the Savage Skulls who were the last remains of the infamous South Bronx gangs. It's an interesting insight into uptown New York before the general gentrification, and it's an intimate look at a sub-culture(?) that became widely caricatured by films such as The Warriors, and other such stereotypes. It still feels exploitative (despite arguments of the contrary) but definitely worth looking into.
here's the first 15 minutes: