Mustacio is right. Have you guys not heard of the subconscious mind? that's what it is man. It stores everything that ever happened to you including people you met, places you visited etc. It's there forever and while dreaming, as your conscious mind goes to sleep, your subconscious mind is still awake and that is how the connection is made to the dreams. Think of it as a computer with a hard-drive. You can access the files that are stored on that hard-drive. You can't access something that doesn't exist on the hard drive. You are able to manipulate and change the way those files appear to you or merge them together but you can't add files or data that doesn't exist.