Here is the magnificient choral improvisation for organ on "Nun danket alle Gott" (Now thank we all our God) by Siegfried Karg-Elert (1879-1933) - a really stunning piece, especially on a cathedral organ.
GPO organ in use here - hope you enjoy!
Eugene, the rendering and interpretation of this piece is top notch and the reverb is perfect. Someone mentioned just the other day there is a shortage 20th century organ music on the Forum. It seems you have well stocked library of organ music. I enjoyed this very much. Thanks for posting.