"Hamburger Concerto" by Dutch band Focus is a virtually perfect album, IMHO, and it includes some real prog pearls, so please browse my blog and you'll find some of them. It also features this "La Cathédrale de Strasbourg", written by keyboardist Thijs Van Leer, one of the strangest, most original and most charming tracks I've ever listened to. This was intended to describe the gothic monument dominating Strasbourg, in France. You won't find for it a definite model among the internationally acclaimed bands of the '70s: this is the pure essence of creative music.
The cathedral and its single belltower dominating Strasbourg.
The song starts with its main theme, a beautiful melody, played on the piano and on a pipe organ (there's a cathedral in the title, after all...), then a choir breaks the previous almost religious mood, singing in French La Cathédrale de Strasbourg, ding dong, ding dong, la nostalgie se réveille, meaning "Strasbourg cathedral, ding dong, ding dong, nostalgy wakes up". Another change and here you are a soft, liquid, jazzy improvisation section, mostly based on guitars. And, of course, in the end the main theme comes back with the choir replacing the pipe organ. So many changes, still the track is perfectly coherent and you reach its finale wondering what this was exactly and definitely loving it.