In The Angry Red Planet (1959) (aka Marte Di Struggerà A Terra), producers Sidney W. Pink and Norman Maurer created a process called CineMagic that made the surface of Mars look truly otherworldly. As explained on Wikipedia, "the method employed the printing of a positive and negative monochromatic image on the same film, essentially turning the camera into a detector for drastic changes in brightness, such as on the edges of a light figure against a dark background." The end result was a vivid red affair that anyone who has seen the film is sure to remember. I particularly like this description, from DVD Savant's review of the film:
Mars in Cinemagic was blood-red, with white and yellow highlights. The image looked very flat, and the still jungle landscape seemed very dead and very alien. It wasn't just tinted red. Some parts of the image were like a negative. Areas that should have been in shadow were instead a glowing, burnt-out white. Relative shadings of dark and light were off balance, so normal clues to perspective and texture were not always present. Trees were reduced to their dark outlines, faces became masks without detail, and a lake looked like molten metal instead of water.
As an added bonus, CineMagic made the film's human actors and rubber monsters look equally realistic (or, if you're a glass-half-empty person, equally fake). Click through for the film's breathtaking Italian poster, a trailer, and a clip that shows the effect of CineMagic.