Alice had quite the imagination. She could create a full episode of cartoons anywhere she went. Yes, that's right. Wonderland was all in her imagination, at least in my opinion and the opinion of many others too. She made those things happen simply by creating them in her mind which is what imagination is.
When an author writes a book, he or she does the same thing. While some say the whole book and movie is about drugs, that is only because they lack the knowledge of what true imagination really is. The imagination is very powerful. If you don't believe that...go ask Alice!