Who Built Stonehenge?

Why anybody would build stonehenge is such an obvious question, and it's been asked right from the very beginning. The basic reason we don't know is that this was wildly prehistoric, millennia, back into times before there were any written records. Fundamentally, i think we can safely say that there would have been a mixture of reasons in the minds of people building stone engine. I haven't mentioned the allignment on the sun. It's aline very clearly on the rising sun at midsummer, in the opposite direction, the setting sun at midwinter. These things are all part of stonehenge, and have to be part of any explanation we try to come up with