The 2012 Billboard Music Awards are taking place in Las Vegas later today and, if years past are anything to go by, that means we're in for some ecletic beauty looks. Over the years we've seen Frida Kahlo-inspired hairbands, rockabilly pompadours, bindis — and that's just from Gwen Stefani! Take a look back at some of the most memorable moments from past Billboard Music Awards including vintage snaps of The Spice Girls, Nicole Richie and more!