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While her peers stuck to pinned bobs and hairspray-sculped flips, the eternally stylish Audrey Hepburn stood out with a close-cropped pixie cut.

It's the platinum blond curls that truly mark country girl Norma Jean Baker's official transformation into the world's most famous sex symbol: Marilyn Monroe.

Her sharp, side-swept pageboy crop made doe-eyed model Twiggy an emblem for swinging '60s style.

Cher's stick-straight hair has proved an inspiration for the flat iron's four-decade domination.

Mia Farrow's 1967 Rosemary's Baby cut is the work of the late, great Vidal Sassoon.

Madonna's hair evolution is so dizzying, it's hard to choose our favorite look, but her sky-high Blond Ambition pony is a standout.

Millions of girls brought this very picture into hair salons back in the mid-nineties and said, "I want to look like this."

Sarah Jessica Parker's hair has settled down quite a bit since season one of Sex and the City, but we miss her wild curls.

Katie Holmes morphed from girl-next-door Joey Potter to Hollywood powerhouse with this sleek bob.

Michelle Williams' sweet, short crop is just like her red carpet style—conservative, yet utterly feminine.

Gwen Stefani's not afraid to experiment—remember her blue-hair phase? Or her cornrows?—but we like her signature platinum best.

Marlo Thomas got the '70's flip exactly right in That Girl.

French sexpot Brigitte Bardot was known for the pouf long before Snooki.

Amy Winehouse's towering beehive was completely not of this world. But, then again, neither was her incredible talent.

Leave it to Victoria Beckham to reinvent the bob again and again.