Jimi Hendrix might be the most well-known left-handed guitar player of all time, but Black Sabbath's Tony Iommi is often considered the godfather of metal guitarists. His work on Iron Man landed him at No. 7 on the list of greatest guitar riffs of all time, according to Guitar World. "The main riff is in B minor, using powerchords that follow up the pentatonic scale before more dissonant-sounding slides from the minor 6th to the 5th – all fretted on the thicker strings for a fuller sound and further intensified by drummer Bill Ward’s snare hits," Guitar World wrote. "It’s this juxtaposition, the lethargic opening segment against its busier second half, that demonstrates Sabbath at their most memorable, mutating familiar bluesy roots into something darker and doomier." 'Iron Man' Came to Tony Iommi on the Spot In a 2021 interview with Songfacts , Iommi revealed how he created the song’s most defining feature, the riff.  “I was in a rehearsal room, and Bill started playing this boom, boom, boom.…