Ahead of Radio 3's 'Breaking Free: A Century of Russian Culture' season, Tom Service unlocks the mysteries of Shostakovich's baffling late masterpiece, his Symphony No. 15. Why does Shostakovich create a nightmarish toy shop soundscape in the opening movement? What compelled him to include musical quotations from Rossini and Wagner? And how does that final movement represent perhaps the greatest act of nihilism in musical history? To answer these questions Tom is joined by this week's Listening Service witness, the music historian David Metzer.