Codex Seraphinianus (or what Tolkien might have created should he have taken acid)
I’ve heard about this book before (and seen some images) but it was my friend who sent me this article reminding me that such awesomeness exists (and that you could download said awesomeness). The Codex Seraphinianus is a visual encyclopedia of an imaginary world created by Italian artist Luigi Serafini. You might even recognize some images from it and never have known it belonged to this mysterious book.
As the article says, you can download it here and see all the imagery for yourself.
Take my word and download it, you won’t regret the weirdness throughout.