I have been to Stonehenge several times. This picture was taken in 2004. It is one of the worlds most famous prehistoric monuments. There is a lot of speculation and theories about its origins but it remains a mystery.
Recent discoveries based on underground imaging and excavations reveal that Stonehenge wasn't the stand alone structure we see today. Instead, it was part of much larger complex web of structures that are only beginning to be explored
http://www.bbc.com/travel/story/20170713-why-stonehenge-was-built