Sound mirrors, reflecting sound waves, are known as acoustic mirrors or sound mirror. They were used in the UK during the Second World War to detect certain sound waves, coming from enemy aircraft. That was before the radar came on. These mirrors were built around the coast of Britain, the most famous of them still stand in Dengue, shire Kent. Just so you can not approach them, access is limited - you can only see mirrors on a special excursion.World's only acoustic mirror outside of the UK is located in Maktab, Malta. This is one of the largest mirrors in the world — its diameter is about 61 meters. In the local dialect the mirror is also called « Il widna » , which means in translation « ear » . Location of the " ear " is not a secret, but free access to it is closed.
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