It's no secret that the world is obsessed with celebrity hair, from the latest cuts to the hottest colours. But no matter how many stars get lobs or pixies, most of them could never compete with the most iconic transformations of our time. We're talking about the ones that inspired trends that would last for decades, make careers, and break our hearts. If you're thinking Twiggy's crop or Jared Leto's man bun, you're right.