About a century ago when filmmakers couldn't shoot some locations due to physical or financial limits, they invented rear projection. They projected the image of a needed location on the screen, immitating the background, and put some real props and actors in the front of it. Thus two spaces were combined and looked as a united one in a film. This technology existed for nearly half a century until green screen and visual effects appeared, which solved problems with limitations of projected images, bulkiness and noise of projectors, immobility of actors, etc. But in return green screen placed filmmakers in artificial space where they constantly had to imagine the final result, and in fact made the entire look of the film in post-production. This pushed filmmakers to invent the "new method".