The "Tristan Chord," introduced by Richard Wagner in his opera "Tristan und Isolde," revolutionized music. This dissonant chord defied traditional tonality and resolution rules, paving the way for modern music's exploration of harmony and dissonance. It encapsulates the shift from classical forms to emotive, unresolved romantic tension, subtly influencing genres beyond opera. Have you encountered a piece of music that challenged your expectations or transformed your understanding of harmony? Share your experience!