20 Most Important Hard Rock Albums Of All Time

Though Rush may have planted the seeds of prog metal in the late 70's, there was still plenty of work to be done. Across the 80's and 90's, bands like Dream Theater and Queensryche started coming to the forefront showcasing grand epics of rock and roll grandeur. Many of these bands may have blown us away with their intensity, but Tool's music ended up speaking to the reptilian side of the brain.

Originally starting out as a straightforward metal act, Tool started to blossom at the start of the 2000's with their colossal album Lateralus. Instead of taking elements of their earlier sound further, Tool took a deep dive into progressive material and psychedelic atmospherics with songs like "Parabola" and the title track. The songs may have seemed a bit off-kilter, but the inner mechanics of each track were jaw-dropping, from the shifting meter of "Schism" to the fact that the title track features a complete Fibonacci sequence in the drum pattern and syllabic structure.

In an era when metal was still being looked at as Neanderthalic music, Tool showed that it was possible to create complicated music that was still rooted in heaviness. Lateralus may be a bit of a heady listen, but once you settle into its groove, it's the most rewarding headbanging you'll ever do.