What could have happened – what should have happened – if two giants in film history, like Greta Garbo and Sergei Michajlovič Eisenstein, could have declared their love for each other? The world's most famous actress, an honorary Russian citizen of cinema for her many performances; the world's most radical director, who could have immortalized her face in one of his famous close-ups? Sphinx Garbo did not want to be alone: she just wanted to marry the great Sergei. Perhaps she could have played Trotsky or Pancho Villa in one of his films. Perhaps their friends Charlie Chaplin, Walt Disney and Josef von Sternberg would have approved their love. Maybe they could have had a child together. Maybe all this could still have happened, in a Mark Rappaport film.

• Documentary