Stereoscopic films had been around since the 1920s, but the 1950s was unquestionably the golden age of 3-D, with excited teenagers flocking to the cinema to see such classic fare as The House Of Wax, Dial M For Murder and The French Line (or "Jane Russell in 3-D!" as it was marketed).
The plot never actually mattered in a 3-D movie. Forget boy meets girl, boy and girl fall in love, boy dies at the hands of a sadistic German U-Boat captain . . .
All a 3-D movie needed was a man with a stick. All that is required is that at some point in the movie he point that stick out towards the audience so in 3-D terms it looks like it's coming straight at them.
The other downside of 3-D movies was that they weren't really date movies. For a start you were required to wear stupid glasses with coloured lenses . . .
The format fell out of favour in the 1960s, replaced by drugs which - if taken in the right quantities - could make everything come at you in freaky 3-D. Even things which only existed in your mind!
3-D movies made a short return in the 1980s.
Unfortunately some of the worst movies ever made were produced to take advantage of the effect - possibly the worst offender being Jaws 3D, although Amityville 3D, Friday The 13th Part 3 and Freddy's Dead: The Final Nightmare (aka A Nightmare On Elm Street 6) all took turns to hammer nails into the medium's coffin.