Maurice Sendak’s Where the Wild Things Are first roared its terrible roars on this day in 1963. Today marks the beloved book’s 50th anniversary. Sendak’s tale about a young boy whose imagination transports him to a land full of “wild things” was an early, rare portrait of the dark emotions children learn to cope with. “If I’ve done anything, I’ve had kids express themselves as they are, impolitely, lovingly… they don’t mean any harm. They just don’t know what the right way is,” Sendak said of the book in a 2004 interview. The many monsters in children’s literature have helped young readers face their fears, empowering them — and in some cases, frightening them to tears. We love them all, so we’ve selected 13 of the greatest monsters featured in children’s books. Tell us your favorites, below.