Before the the invention of radar, acoustic mirrors were built as early warning devices around the coasts of Great Britain, with the aim of detecting incoming enemy aircraft by the sound of their engines.
photo credit: Stephen Birch Photography
The acoustic mirrors, known colloquially as ‘listening ears’, at Denge are located between Greatstone-on-Sea and Lydd airfield, on the banks of a now disused gravel pit.
photo credit: Peeteekayy
The mirrors were built in the late 1920s and early 1930s as an experimental early warning system for incoming aircraft, developed by Dr William Sansome Tucker.
Several were built along the south and east coasts, but the complex at Denge is the best preserved.
The Dungeness mirrors, known colloquially as the “listening ears”, consist of three large concrete reflectors built in the 1920s–1930s.