You may not see a Portuguese man-of-war when you're swimming in the ocean. Yet that doesn't mean you're safe. A man-of-war's tentacles are so long--up to 165 feet (50 m)--that a swimmer could brush against them and get stung without ever seeing the creature. A sting from the man-of-war is extremely painful, but fortunately it usually isn't strong enough to kill a human. In Portuguese Man-of-War: Floating Misery, kids will learn all about the natural...