There is no other word to describe this book. I saw it on Goodreads and loved the cover (I know you shouldn't judge a book like that, but I thought what the hell). It's absolutely mesmerising and I couldn't put it down. The story is both fantastical and heart-wrenching. A beautifully detailed story about a world which may lie beneath our feet. The illustrations are wonderful. If you can, make this one of your first reads of 2017!