Stonehenge

I'm sure you know that Stonhenge, the stone circle north of Salisbury, England, is a World Heritage Site. You have read about it or have been there yourself. Scientists disagree on exactly when this monument was built and how. Previously, it was believed that it was built 5500 years ago, or even earlier. Was it an observatory, a sanctuary or a druidic temple? The stones are tons, not all from the area. How was it possible to transport them and set them up?
What do you think?