CaptionFrom the mop top to the mullet and every style in between, here are some of the most memorable hairstyles sported by celebrities over the past 100 years.Getty ImagesIs the total lack of hair a style? It was for Irish singer Sinead O'Connor, shown here in 1989. O’Connor would find herself deep in controversy for tearing up a photo of Pope John Paul II in 1992 during a musical performance on TV’s “Saturday Night Live.” The shaved look—particularly on women—has sometimes been attributed to as a symbol of control. Actresses Demi Moore and Sigourney Weaver sported the look for signature acting roles. O’Connor once explained to a reporter: “I don't feel like me unless I have my hair shaved. So even when I'm an old lady, I'm going to have it."