Pennsylvania musical rocks
Looking at the boulders that dot the Ringing Rocks County Park (PA), it seems to see a show already seen hundreds of times throughout the world.
But those stones are everything but common. In fact, a simple beat against them produces a metallic sound. If you wouldn't know we're talking about rocks, you'll probably say the sound produced is due to some metallic objects. But this is not the case!
The nature of this strange phenomenon has perplexed scientists for years, and even today there are various assumptions, but it is not known yet why these rocks produce this unusual sound.
It seems, from studies, that these rocks are made of a substance called diabase which is basically volcanic basalt.They also have a high content of iron and aluminum, which explain the metallic behaviour. But the weird thing is the sound. In fact is not the single rock to resonate, but all the nearby ones: the hit given from an outer source produces low frequency vibrations, which start a resonance with all the nearby rocks. But if there is a theory about how this sound is made, it hasn't been discovered yet.
Also the location is quite unusual: in fact, the arrangement of these stones make scientists think that are the result of an ancient mountain landslide, but instead of being at the bottom of a valley, they are located on top of a hill. Really disarming for everyone who supports this idea!
There aren't even signs of a glacier, which is presumed to be an hypotetical cause of this strange position. So the presence itself of these monoliths is a mystery! Others have more fanciful explanations such as radioactivity, meteorites, comets, or strange magnetic fields. Even supernatural possibilities have been suggested, and the area has been studied by those with an inclination for the paranormal
But, despite the things we don't know about it, we can always go to Pennsylvania and make one heck of a concert by simply using some hammers: