I've watched quite a few hip-hopumentaries now and each one is a little bit different. "Rhyme & Reason" came out in the late 90's featuring the best artists during the golden age of hip-hop. "Hip-Hop Evolution" is a more recent Netflix mini-series that is very educational. "Beats, Rhymes, & Life" focuses solely on A Tribe Called Quest. Ice-T's "Something from Nothing" is a bit of "The Show" and "Rhyme & Reason" with a focus on rapping. Ice-T goes from the East Coast to the West Coast with a stop in Detroit to interview some of the legends of hip-hop.
