Conversation so far:
What does St. Francis have to do with Olivier Messiaen?
Saint François d'Assise is an opera in three acts and eight scenes by French composer and librettist Olivier Messiaen, written from 1975 to 1983.
What was the piece Olivier Messiaen composed with St. Francis?
Saint François d'Assise is an opera in three acts and eight scenes by French composer and librettist Olivier Messiaen, written from 1975 to 1983.

Question: What are the canyons?
Self-contained rewrite: What are the canyons mentioned in the Olivier Messiaen article?