The Outlaw (1943)

Because it had to start somewhere. And no, I'm not talking about flashing thighs in Busby Berkeley numbers, or Claudette Colbert's leg in It Happened One Night (1934) or Fay Wray almost topless in King Kong (1933). Instead, The Outlaw is the movie, more than any other, where the decadent and often leery subtext of Hollywood product (what is King Kong, other than an interracial sex fantasy?) comes spilling out over the surface, and encapsulates the entire project.