A new theory surrounding Stonehenge, which in the past has been suspected to be some sort of temple or sundial, has surfaced regarding the noise it makes when you hit it with a rock. The rocks make a loud clanging noise when hit which leads to the theory that the ancient monument is actually an instrument used to make music. It certainly would explain why the rocks were hauled 200 miles which is a huge feat for 4,000 years ago. While it is still just a theory it would explain a lot of the mystery behind the monument. Read more about the theory here.