Filmed on location in seven different states during 1980-1981, Americaâs most loved and original music genre is the subject of âThatâs Bluegrassâ. This care-free, fast-moving documentary lovingly examines our home-grown musical heritage from the simple front porch fiddler to famous Nashville recording stars, listening in as accomplished amateurs do some âpickin and grinningâ at outdoor festivals and play songs handed down from generation to generation.