Standing silent and abandoned, a series of isolated and mysterious concrete structures line the south east coast of England. Known locally as "listening ears", these structures, more properly called acoustic mirrors, are vestiges from great inter-war acoustic experiments to create an early warning system against the possibility of an airborne invasion across the English Channel.

The acoustic mirrors tilted their faces to the sky and collected sound in giant concrete dishes. They were operated by trained listeners that endured cold nights at their listening posts, entombed in concrete bunkers, or high on listening platforms in front of the mirrors, to pick up distant noises from the sky.

The acoustic mirrors were never used in wartime - the invention of radar and the increasing speed of aeroplanes rendered them obsolete within ten years of their erection. Almost seventy years later, these now forgotten experiments have become the focus and the inspiration for a groundbreaking international art project - an attempt to re-invent this redundant technology for the 21st Century.