Christopher Nolan’s Dunkirk is a nerve-wracking film. Three separate storylines tell the famed World War II tale — where 330,000 Allied forces, surrounded by the enemy, were evacuated from the Northern beaches of France — in a way that feels tense and visually stunning.
Built around a score by composer Hans Zimmer, Dunkirk hardly ever slows down from start to finish. And a lot of that has to do with how Zimmer uses an auditory illusion caused by Shepard tones.
Named after cognitive scientist Roger Shepard, the sound consists of several tones separated by an octave layered on top of each other.