Musician's Challenges


Down further I started list of challenging musical compositions that test the quality of the musician.
Please add and continue!

Guitar:
1. Recuerdos De La Alhambra by Francisco Tarrega best played by Pepe Romero IMHO
2. Le Catedral by Augusin Barrios best played by Ana Vidovic
3. Las Abejas by Augustin Barrios best played by Jason Vieaux

Piano:
Obviously it's Rachmaninoff#3 played by Ashkenazy... anyone better?
There are also great sophisticated set of Chopin ethudes that I'm lost which one is more challenging than the other so there's room to share.
czarivey
From the purely technical viewpoint the most difficult music to play might be the one not designed to be played by human. Conlon Nacarrow music written for pianola was impossible to play because of speed and impossible fingering. I've heard that today few pianists can play it:

http://www.youtube.com/watch?v=LFz2lCEkjFk
"From the purely technical viewpoint the most difficult music to play might be the one not designed to be played by human."

Hmm, technology bettering humans? We know machines are better at some things. Luckily, the machines do not work without a programmer. Maybe learning to program a synthesizer while oozing charisma is the way to go :^)
Mapman, Conlon Nancarrow was originally composing music for piano but when his music got very complex he couldn't find pianists to play it (especially in Mexico where he lived). He switched then to pianola and discovered completely new instrument. It is still music, but concept of a his music "Concert" is strange when you sit in the audience and the only thing on the stage is pianola. Why would anybody pay for that?! On the other hand his music played very loud in my room is beyond believe.
Anne-Sophie Mutter's album "Carmen Fantasie" is an example of the artist showing her chops playing very challenging violin solos.

http://www.amazon.com/gp/product/B000001GII/ref=oh_details_o03_s00_i00?ie=UTF8&psc=1

Fast and technical and the violin is mixed far out in front of the orchestra. I've enjoyed Mutter's previous recordings but unfortunately this CD is not much of a collaboration between soloist and orch as Itzhak Perlman has always done. But it is audiophile quality and worth a listen.
So we're agreeing that the words "quality of the musician," in this context, means "chops?"

I was hoping this was going to be about musicianship and not athleticism.