Katie Derham looks at the response from the world of ballet to the music of Bach with the American dancer and choreographer Mark Morris. The spirit of dance lies at the heart of so much of Bach's music and in recent years choreographers have tapped into this for inspiration for new work - most notably Mark Morris, whose arresting and innovative work for ballet has often made people think the medium afresh. The music of the Baroque has provided him with a rich source of inspiration, including his work with cellist Yo Yo Ma for the series "Inspired by Bach" which resulted in the acclaimed "Falling Down Stairs" - a dancer's response to Bach's Cello Suite No 3.