Duct tapes were first invented by a female factory worker during World War II. Duct tape can hold just about anything together. We use it for all sorts of repairs and even as a decorative addition to various arts and crafts. But what makes duct tape so strong and versatile? And is it duct tape or duck tape? They were originally called 'duck' tape because it was made out of a cotton duck fabric and it repelled water like a duck's back.