10. 1939: Katharine Hepburn
Lighting up the Hollywood scene with her starring role in The Philadelphia Story, Hepburn made waves with her strong sense of style. She wore the structured shoulder dresses that were so popular during the late '30s, yes, but she also wore pants. In fact, she would go to a back counter of Brooks Brothers and secretly buy trousers and shirts since they were not available anywhere else for women shoppers.