A personal "7 Wonders of (classical) music"

I was browsing in another forum yesterday, looking at thoughts on performances of the Rachmaninov Vespers and a poster opined that this was, in his opinion, one of the Seven Wonders of Music - a reference to the Seven Wonders of the Ancient World.

This set me thinking - what would I put on such a list - and came up with (in alphabetical order)

Bach Cello Suites
Beethoven 9th Symphony
Beethoven A minor quartet op 132
Elgar Cello Concerto
Mahler 2nd Symphony
Rachmaninov Vespers
Verdi Requiem
 

Clearly I could add another dozen or two works, but this seven first came to mind.

I'd love to see others' lists, and perhaps other threads for Jazz, Rock etc. could be started but I would not know where to begin in those genres.

Also, I have not referenced specific performances.  I'll think about that and try to post those thoughts later.