h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Once I was visiting Arthur's Stone on The Gower which is known locally as the site of strange lights and going-on (ufo's etc) when a distant thunder rumbled from the direction of the nearby town, just across the estuary, where Merlin was born. Arthur's stone suddenly began to make a noise, sounded a bit like a swarm of bees but at a higher pitch, as if it contained some kind of crystals perhaps. I have a photograph, a postcard bought nearby, which shows a strange glow around the stone.