Music elates, touches the soul and bypasses reason. Music is magic. But precisely this magic can turn it into an insidious weapon for music and violence belong together. The brutal power of African war dances, the ferocity of Maori Hakas, the earth-shattering roar of US sound guns blasting Metallica at Taliban hideouts the principle is always the same: Aggressive sounds demoralise the enemy and whip the allies into a frenzy. In Songs of War, director Tristan Chytroschek explores the extraordinary harmony between music and violence. Sesame Street composer, Christopher Cerf, always wanted his music to be fun and entertaining. But then he learned that his songs had been used to torture prisoners in Guantanamo and Abu Ghraib. He is stunned by this abuse of his work and wants to find out how this could happen.

• Documentary