Bob Dylan's Knockin' on Heaven's Door opens with one of the most quietly devastating chord progressions in folk rock — G, D, Am, G — a movement that feels both inevitable and deeply human. The progression drifts from the warmth of G through the open brightness of D before settling into the minor shadow of Am, then gently returning home to G. That minor chord lands like a held breath, giving the whole sequence a sorrowful, meditative quality that perfectly suits the song's themes of mortality and release. Written in 1973, it sits within the roots-influenced, unhurried folk rock of that era. For guitarists, those four chords are immediately satisfying to play — resonant, uncluttered, and expressive in the simplest possible way.