Visual effects have been a huge part of the movie industry since well... movies began. Adding that extra little touch of magic makes a movie that much better and there are millions of ways to do that.
Take a look at these shots from some of the biggest films. Weather they are old or new, you can see how they achieved the shots. From high tech green screen to simple miniatures shot to look huge, they have done it all so well its almost hard to tell how they did it in the final product.