UNITED STATES - JANUARY 15: HAPPY DAYS - Gallery - Season One - 1/15/74, One of the most successful series of the 1970s was "Happy Days", which was set in the late 1950s, early 1960s in Milwaukee. "Happy Days" told the story of the Cunninghams, pictured, bottom left: Marion (Marion Ross) and Howard (Tom Bosley), the parents of Joanie (Erin Moran), Richie (Ron Howard, bottom right) and Chuck (original actor Gavan O'Herlihy, top right, was replaced by Randolph Roberts in 1974, before Chuck went to college and was never seen again). Richie's friends were Ralph (Donny Most, top left) and Potsie (Anson Williams, top center). Henry Winkler (center, right) played Fonzie, who moved into a small apartment over the Cunningham garage., (Photo by Bob D'Amico/ABC via Getty Images)