Singing Ringing Tree (Panopticons)

The Singing Ringing Tree is a musical sculpture set in the landscape of the Pennines overlooking Burnley, in Lancashire.
Designed by architects Mike Tonkin and Anna Liu of Tonkin Liu, the Singing Ringing Tree is "constructed from pipes of galvanised steel, which harnesses the energy of the prevailing winds", to produce a slightly discordant and penetrating choral sound covering a range of several octaves. Some of the pipes are primarily structural and aesthetic elements, while others have been "cut across their width enabling the sound". The harmonic and "singing" qualities of the tree were produced by tuning the pipes "according to their length by adding holes to the underside of each".