A forerunner of radar, acoustic mirrors were built on the south and northeast coasts of England between about 1916 and the 1930s. The ‘listening ears’ were intended to provide early warning of incoming enemy aircraft.
The acoustic mirror at Kilnsea in East Yorkshire was one of a number built on the northeast coast around the time of the First World War. A forerunner of radar, they were intended to provide early warning of incoming enemy aeroplanes and airships about to attack east coast towns.