Woo-ping Yuen, famed for his choreography of the remarkable fight scenes in The Matrix, insisted that the film's actors study martial arts for four months.

Everyone later agreed that the extra training had helped -- even Keanu Reeves, who showed up on the set one day wearing a neck brace.

[Ang Lee once said of Yuen that "every ten years he does something revolutionary that everyone copies for the next ten years."]