2005
TR0721 : Sound Mirrors at Denge
taken 21 years ago, near to Lydd (London-Ashford) Airport, Kent, England

Sound Mirrors at Denge
These experimental sound mirrors were an early attempt at long-range aircraft detection and were built in the early 1930s. The smaller 20-foot mirror was the first to be built followed by the larger 30-foot mirror. It was intended to have a network of these larger mirrors along the Kent coast to detect incoming enemy action. This however was the only one built - radar came along and they were made totally obsolete overnight.
