Thirty-two wind turbines recreate the sound of horse hooves hitting the ground, in this installation that architecture studio NEON has created at Chesters Roman Fort, in the north of England.
NEON, which is led by architect Mark Nixon, created the Cavalry 360 structure as part of Hadrian's Cavalry – an exhibition taking place at various museums and sites along the 150-mile-long Hadrian's Wall, to recognise the Roman cavalry that guarded it 1,600 years ago.
Acting as a giant musical instrument, the structure is designed to create a soundscape that will inspire its audience to think about the history of the location, which is home to the most extensive Roman fort in Britain, as well as the lives of the cavalryman and horses that inhabited it.
"The challenge of describing something that was no longer physically there and acknowledging the way the horse changed mankind's relationship to the landscape were key to our approach," said Nixon.
"Like written fiction, we were excited to offer a half description of the subject as a means of evoking the imagination of the viewer to fill in the gaps."
NEON chose a circular form for the 12-metre-wide high structure, so that visitors standing inside feel like they're surrounded by noise, and can also enjoy 360-degree views of the surrounding landscape.
It is made up of 32 turbines, which are arranged in pairs to represent a Turma, a Latin term used to describe a Byzantine cavalry unit comprising 30 horses.
Each turbine is powered by a set of three rotating arms, all of which have a large cup attached on the end. As wind rotates the turbines, the motion is transferred to sets of 15 beaters, which create the constantly changing sound of horse's hooves hitting the ground.
Visually, the rotation of the turbines is also designed to resemble the movement of horses' legs.
As the wind gusts in various direction, different turbines are engaged, which provides the audience with the sense that horses are darting around the landscape.
Each individual beater represents a single horse. The volume of the sound increases in accordance to the wind speeds, creating a shift from "trot" to "gallop".
"This should be an incredible experience for our visitors', says Kevin Booth, senior curator at English Heritage, who commissioned the work alongside Arts Council England.
"It is designed to connect the viewer with the environment, to invite people to look through the work at the landscape beyond, to pick up the sound on the wind, to experience the beaters working at differing speeds as the wind rises and falls – and as the horse gallops or trots."
The Hadrian’s Cavalry exhibition is taking place at 10 museums and heritage attractions across the full length of Hadrian’s Wall until 10 September 2017.
Cavalry 360 will remain open to the public at Chesters Roman Fort until 5 November 2017.
Mark Nixon founded NEON in 2012. Other projects by the studio include a vibrant tent-like installation in France and a structure with shingles that "shiver" in Finland.