Probably because we were just recently in Washington Square, NYC, this oldie but goodie seemed to jump off the shelf at Hollywood Video (along with the final episodes of Lost season 2).
The arch and famous fountain appear a few times in this animated feature, plus I dimly recall coming over from JSQ to attend a talk by Ralph Bakshi himself, closer to the time of this film's release (1981), at some NYU lecture hall also next to the park.
American Pop begins in Czarist Russia, where a mother and son escape a pogrom -- the rabbi dad falls to the sword, insisting on finishing his prayer.
After the mom dies in a garment factory fire, the son gets absorbed into Vaudeville, gets wounded in WWI (losing any chance for a good singing voice), marries a stripper, and eventually becomes a petty crime boss in Gangsterland USA (in part thanks to his own son's arranged marriage).
This next son, an accomplished pianist, enlists in WWII and is shot while playing, leaving his eldest to haunt Greenwich Village (enter the arch) and soak up its beat culture.
He makes his way, by stolen car and hobo train, to the drug, rock and anti-war scene in California -- by way of Kansas where a fling in the corn field begets a fourth generation (this we find out only later).
The last son ends up taking care of his washed up druggie dad (they move back to New York) who eventually abandons him (after first pawning the boy's guitar), and becomes the street smart punkish cocaine dealer with lots of music in his blood.
This last son becomes the superstar for the climax of this story, and although he's blue eyed and blond, all that American Heritage, Jewish included, is carried forward in the music, perhaps completing the great grandfather's prayer in some dimension.
The film uses interesting techniques, painting over live actors while sometimes splicing in raw documentary footage to add realism. Whereas the characters are fictional, the music is the real deal, popular American hits from throughout much of the last century.
For 12-year-old Tara (and for me), I thought this was a good history lesson, especially in complement with the EMP exhibits in Seattle and Nashville's Hall of Fame and Museum of Country Music. Follow the memes, study the genesis of your culture.