Franz Liszt's "Hungarian Rhapsody No. 2"
John Coltrane's "Giant Steps" (This song is notorious for the sheer difficulty of its chord progression, introducing a new kind of harmonization called 'Coltrane Cycles': https://en.wikipedia.org/wiki/Coltrane_changes).
Rock and Pop:
Queen's "Bohemian Rhapsody" (Sticking with the 'Rhapsody' train). This song is often cited as one of the greatest rock songs ever, and notable for its operatic grandeur.
As a treat, here's an additional article. 50 years ago this summer, The Beatles released Sgt. Pepper's Lonely Heart Club Band--an album that critics simultaneously labeled as a legitimizing record for pop and rock music, and lamented as a harbinger for the death of rock. Clearly, they did not foresee the resurgence in popularity of rock music in the 70s and 80s. However, it was almost 30 years to the day after Sgt. Pepper's was released that another rock record came out--one that actually seemed to spell doom for rock music and for the analog world as we knew it. That album was Radiohead's Ok Computer, now 20 years old and as of this week shining in a spectacular new remastered edition. The album seemed to have prescience about our current world, echoing with sentiments of a burgeoning technocracy, and the rise of paranoia in a machine-driven world. OK Computer is as much of 2017 as it was of 1997. And besides its social prescience and capturing of a tangible mood in the ether, the album also changed rock music after it. Sgt. Pepper's allegedly marked the death of rock music, but OK Computer seemed to actually dispense of traditional rock 'n' roll forever. Here is a piece from the New York Times detailing how music changed in the wake of this monumental album.
Have a great Monday, all!