One of them names the most important school of European composers of the early 13th century.
A piano piece titled for one of these places opens with a series of parallel fifths that evoke the disorientation of fog before crescendoing to a fortissimo passage marked Sonore sans dureté [so-nohr san doo-re-TAY]. A group named for a specific one of these places included the organum masters who wrote the Magnus Liber; that most prominent school of ars antiqua composition, which is named for one of these places, included the composers (*) Leonin and Perotin. Claude Debussy's Preludes include a piece depicting a "Sunken" one of these structures from legend. One of them names the most important school of European composers of the early 13th century. Britten's War Requiem was composed for the consecration of one places damaged in Coventry. For 10 points, identify these musically-important buildings, one of which lends its name to the Notre Dame school.
A piano piece titled for one of these places opens with a series of parallel fifths that evoke the disorientation of fog before crescendoing to a fortissimo passage marked Sonore sans dureté [so-nohr san doo-re-TAY].
cathedrals [prompt on churches; accept The Sunken Cathedral or The Submerged Cathedral or The Engulfed Cathedral or La Cathédrale engloutie]