A musical composition set in a stone sculpture in Fairlop Waters, Essex, has opened to the public.
People are encouraged to get close and touch the sculpture which is made from Angel Stone (or Gneiss). Their movements trigger a number of motion sensors which are set within the sculpture. The piece emits different sounds depending on how people approach it.
The natural sounds and music were recorded in South Africa and include a vocal melody sung by the University of Johannesburg Choir. The project was conceived by Mira Calix who says "the whole thing is a song".
The work, which is called 'Nothing Is Set in Stone', was commissioned for the Mayor of London Presents Festival and will be open until September 9. Boris Johnson says he hopes it draw visitors to the area.