Octavarium by Dream Theater: This song actually has five movements, and it clocks in at 24 minutes; 24 minutes of pure contemplation about the cyclical and paradoxical nature of the universe by basing it on the concept of the musical octave and the golden ratio. Frankly, this is one of the most prolific progressive rock pieces I’ve ever listened to ever since Pink Floyd’s Dark Side of The Moon because of its grand concept (and the various “easter eggs” buried throughout the whole album)
PS: With this album’s concept, Nietzsche’s “Gay Science” come to mind, haha. “This life as you now live it and have lived it, you will have to live once more and innumerable times more; and there will be nothing new in it. The eternal hourglass of existence is turned upside down again and again—and you with it, just a speck of dust!”
