The Romney Marsh sound mirrors that were built to protect Britain

More educative entertainment from Tom Scott, this time testing out the huge concrete sound mirrors that were built in pre-radar days:

The Sound Mirrors, on Romney Marsh, were built in the late 1920s as a way to amplify the sound from aircraft engines over the English Channel.

Radar turned out to be much the better technology, however. (Although – myth-busting digression – radar was not something that Britain had and the Germans didn’t in the early days of the Second World War. Rather, the British edge was in information management, making much better use of the information from technology that was actually inferior to the German radar technology.)