Rocky Balboa, the underdog palooka who boxed his way to box office super-success, burst into popular culture in 1976. Now 45 years later, "Yo, Adrian" has joined the very short list of very short quotes that are instantly identifiable with a classic character from a classic film. Tourists still run the steps of the Philadelphia Museum of Art. Marching bands play "Gonna Fly Now" as halftime entertainment. High school football teams get crazy-eyed to "Eye of the Tiger." LIFE Rocky looks back the story conceived by actor and writer Sylvester Stallone and the iconic 8-film franchise it has become, celebrating Rocky's friends, his foes, his fights and the songs and scenes that endure today.