Book Nook in a fireplace that is no longer usable. Very creative use of space. Just make sure to clean that fireplace well before putting any books in there and to seal things to prevent water damage or pests from coming down the chimney.
Clever design solutions to STORAGE - BOOKCASES & SHELVING (I have always loved BOXES! (in this age of e-readers and e-books - still love hard-copy books)… Bookcases in a hallway/pass-thru. That's right exploit every single space possible.