Just when you thought it was safe to start showing off again, the QI team are back with another lorry-load of common mistakes and misunderstandings. Whether it's history, science, sport, geography, literature, languages, medicine, or common wisdom, you'll be astonished to discover that everything you thought you knew is still hopelessly wrong. Octopuses have two legs. Oranges aren't orange. Bats aren't blind. Napoleon wasn't short. Vikings didn't wear horned helmets. There is no such thing as a fish.