10 Greatest Prog Rock Bands

At the band's inception, many people probably wouldn't consider Tool as contenders for one of the greatest prog bands of all time. Sure, the band's first step up to the plate with Undertow was a solid metal offering, but it wasn't necessarily overflowing with shifting meters and elaborate production. Make no mistake, Tool were not a great prog band in their early years, but they did turn themselves into one.

As the band went into their next records, the riffs started to become much more varied, with songs that were either set in a weird time signature or had an offbeat structure. If the final song from Aenima "Third Eye" showed the band going into complicated directions, Lateralus was the quantum leap into uncharted territory, where the band won the hearts of both music theorists and metalheads alike with rock solid songs that had everything from Eastern sounds to songs that change time signatures at nearly every other bar.

Knowing what they had cultivated, the band doubled down on 10,000 Days, with songs fitting together almost like individual suites like the Wings for Marie sequence. With Fear Inoculum still bringing the heat in full force, the passage of time has not been a hindrance to this band's thirst for the unconventional musical approach.