The title of Daniel Geller and Dayna Goldfine’s documentary is a bit misleading: its subject isn’t Diaghilev’s groundbreaking Ballets Russes, companies whose collaborators included Debussy and Picasso, but two successor troupes that started up after Diaghilev’s 1929 death. From the snippets of fuzzy archival footage it’s hard to get a sense of what whole performances were like, and there are few contextualizing comments to illuminate the choreography’s significance. But the troupe veterans interviewed, most in their 80s and 90s, are wonderfully passionate; the affecting ending shows them still working as dance teachers and archivists all over the world. 119 min.