Seventy years ago this month, The Wizard of Oz opened and began a career in which it has been seen by more people than any other movie. But it has one other great distinction: no Hollywood film has been more dogged by rumour, legend and myth. To mark the anniversary of the world's most famous movie, we set out to see what, if any, substance is in these claims. To do so, we interviewed all but one of the surviving members of the cast, each of them actors who played Munchkins. The result is 2009's version of what really happened on the Yellow Brick Road.