1. Rita Hayworth
Natural hair color: Black
Why she went red: Few Hollywood stars were manufactured as deliberately and effectively as Hayworth. She was born Margarita Carmen Cansino in Brooklyn; both of her parents were in entertainment, and Rita was discovered in a father-daughter act, "The Dancing Cansinos," in Tijuana. The young Latin dancer showed potential and was obviously gorgeous, if only she wasn't so... Latin. The studio dyed her hair a lush red, gave her electrolysis to achieve a higher, more rectangular hairline, and re-introduced her using her mother's Anglo maiden name. Et voila, one of the great screen sirens in movie history.