Thanks very much. I was afraid that no one would reply or that I had asked a silly question or something! I hope it turns into an interesting topic. I don't really know what the site could be for, that is why I am investigating it. There are many theories that sound plausible when someone who really believes in them justify them. Especially a proffessional archaeologist! One theory I am inclined to lean towards is that monuments such as this appeared when agriculture did and symbolize territory. This would also show the change in attitudes to the land eg it could be owned. Henges could therfore symbolize a great change in attitudes to nature and humanity eg how people saw themselves as separate from the land and animals, so in some peoples eyes, more human.