Black Sabbath's Tony Iommi is a godfather of heavy metal, but his career was almost cut short. As a 17-year-old, Iommi was involved in an industrial accident that resulted in the loss off the tips of middle and ring fingers on his right hand.

As a result, Iommi adjusted his approach to guitar, with down-tuned strings to ease his playing. The end result created a signature sound for Black Sabbath. What could have been a tragic accident in some ways turned out to be a blessing for heavy metal music, but had the accident been worse, heavy metal music as we know it may have never existed.