The Rite of Spring — Igor Stravinsky

Stravinsky's 1913 ballet score ignited a near-riot at its Paris premiere, but its savage rhythms and dissonant harmonies proved revolutionary, influencing 90% of film-score composers by the 1950s. It single-handedly ushered in musical modernism, and its rhythmic complexity remains unmatched—more aggressive than any piece by Debussy (#5) and structurally more daring than Bach's Well-Tempered Clavier (#8) in its harmonic language.