1. Nirvana, "Smells Like Teen Spirit" (1991)
The song that blew up the world. The song that defied all rules about how music worked and how much raw emotion you could cram into four cheap chords and a crummy guitar solo. The song that kicked the future in the teeth. The song that shattered all your complacency about settling for the politics of the inevitable. "Smells Like Teen Spirit" was Kurt Cobain's challenge to the audience – and after all these years, the challenge still stands.