Cannes 2017: An extra-special Palme d'Or to mark festival's 70th birthday

It's the holy grail for every film director at Cannes. The Palme d'Or, or golden palm, is the trophy awarded to the film judged to be the best in the competition. But what is the significance of the palm leaf, and how is it made? This year, a special diamond-incrusted edition has been designed for the winner of the 70th Cannes Film Festival. Report by Olivia Salazar-Winspear, Pierrick Leurent and Claire Williams.