England's Ears

Took a walk today around the Hythe area on the Kent Coast facing the English Channel, and came upon a dilapidated piece of classic British scientific inventiveness set high up on the hill overlooking the town.
It turns out that in the 1920's -30's, prior to World War II and the invention of radar, work was going on all along the Kent coast to build large sound reflectors, or acoustic mirrors. They were built as early warning devices, with the aim of early detection of airborne invasions from the continent. This was one of them, the others being at Dungeness, just along the coast.
There seem to have been many designs but this one on the Roughs above Hythe is similar in design to the latter radio telescopes used to receive radio waves from space. It is basically a large reinforced concrete bowl about 5 metres across, with a stethoscope type microphone placed out from the centre where the sound waves were all focused at one point. Clever, but along came radar and the technology became defunct and the sites derelict.
Sadly it has been vandalised in recent times, and now there is a wire fence all around it to protect it - but not from the elements which are taking their toll. I had to stand on tiptoe, holding my camera aloft to take this view. Looking at the state of it, I don't think it will last that many more years before it completely falls to bits.