It used to be that what you saw on a movie set would pretty much be what you saw in the final movie. If you wanted to have a mountain in the background, you’d have to go to one. However with modern technology, CGI has made it possible to have that mountain in the background without even leaving your home. Just whip up a green screen and you’re good to go!
This advancement in technology has meant for some big differences between what is filmed and what we see in the final movie.
Here are some Hollywood movies without the VFX applied!