On this day in 1974 the first episode of Happy Days airs, portraying the comic antics of 1950s Milwaukee high school student Richie Cunningham and his pal Potsie Webber. A minor character, super-cool biker Arthur “the Fonz” Fonzarelli, soon came to be the show’s central character. The immensely popular series was the most highly rated comedy in the 1976-77 TV season and stayed in the Top 20 most highly rated shows for seven of its 10 seasons. It launched several spin-offs, including Laverne & Shirley and Mork & Mindy.

(with thanks to History.com)