Released in 1991, Smells Like Teen Spirit arrived like a distress flare and rewrote the mainstream overnight, becoming one of grunge's defining moments. The opening chord progression — F5, Bb5, Ab5, Db5 — carries an almost physical tension. It begins on a root that feels grounded, then lurches a tritone up to Bb5, before sliding chromatically downward through Ab5 and resolving, with a sense of queasy satisfaction, to Db5. That descending pull gives the riff its restless, coiled energy: neither fully settled nor chaotic. For guitarists, the progression is immediately rewarding to play, each shift feeling inevitable once you know it, yet slightly off-kilter enough to hold the ear. The whole thing bristles with suppressed urgency before the drums even enter.