Kilnsea's early warning system
A huge concrete dish, pointing at the North Sea from an East Yorkshire field, was once a vital part of Britain's defence system.
Kilnsea acoustic sound mirror
As part of Look North's Abandoned series, Matt Richards went to Kilnsea to see the acoustic sound mirror, which gave warning of airship attacks during World War One.
The dish acted as a primitive radar, amplifying engine sounds from distant Zeppelins so they could be heard by an operator, who would then send an air-raid warning inland by radio.
Matt met up with local historian Jan Crowther, who said that the long-abandoned sound mirror has become a tourist attraction.
last updated: 15/10/2008 at 14:56