Glacier by Alvin Luciers is a masterpiece. There's not much happening on the 'cello - just a long and very slow Glissando. What it's about are the additional resonances of the instrument itself and the hall, where you play it. That's why a live-performance for this piece is even more important than usually.
On December, 1 2021 Lucier died. Since i couldn't find this piece so far on the net, i decided to publish it despite all arguments against the online-version.