Crop Circles
For hundreds of years crop circles have appeared as a message to man, Crop circle debunkers have even tried to use wooden slats to fool the media into making us believe they are all fake. Low frequency ultrasound can mimic the exploding stem nodes in the real circles. 
Was stonehenge built on an ancient crop circle? Many question remain The truth is out there.
cropcircles cropcircle farming corn field fields circles stonehenge hampshire wiltshire summer 2017 june