Piano Concerto No.23 in A major (2) Wolfgang Amadeus Mozart
Glass' impressively simple score proved so popular that it's become a piece of music in its own right.
It's one of the most unusual films to become a cult classic. Not only does the 86 minute masterpiece consist mainly of time-lapse footage of landscapes across America, but you won't hear a single word throughout the entire film; there's no dialogue whatsoever.
Cue Philip Glass, and his hypnotic score. As the images slide by in slow motion, the simple music provides an equally important soundscape to tie in with the visuals.
Despite the soundtrack's prominence and importance in the film, the complete recording wasn't released until 2009. An original soundtrack was released in 1983 alongside the film, but at only 46 minutes, it acts as more of a 'best of' compilation than a comprehensive album. Glass released a longer version 15 years later, clocking in at 73 minutes.