Stephanie Kwolek is one of the world's most bad-ass chemists, as she worked in the 1960s at DuPont to create Kevlar, one of the strongest fibers in existence. Kevlar has saved thousands of lives with inventions such as bulletproof vests and parts of spaceships. Kwolek's journey was not an easy one, as she was continually passed over for a man. However, she is one of our unsung feminist heroes as she continued to pursue her career in science.