One would have thought that after all these years that this would have long since been proven rather than guessed. Now it is explicitly true. A little more excavation and we may well be able to completely reconstruct the main features of the site and even bring in fresh rock. I would like to see the effect on the mind that it produces as well.
Stonehenge: ghostly outlines of missing stones appear
Archaeologists can now say for certain that Stonehenge was once a complete circle after the dry weather revealed the ghostly outlines of missing stones
By Sarah Knapton, Science Correspondent
8:09PM BST 31 Aug 2014
It is a mystery which has intrigued archaeologists for centuries: did the huge Neolithic stones which make up Stonehenge form a complete circle?
Now the puzzle has been answered after the dry summer revealed the faint outline of the missing megaliths.
Usually the ground is watered by stewards, to keep the earth moist and the grass healthy.
But this year, the hose they used was too short to reach the whole site. By chance, the incomplete section of the inner stone circle was left to dry out.
When archaeological features have been buried in the ground for a long time, they affect the rate that grass grows above them, even long after they have disappeared.
In the past heatwaves have picked out the eerie outlines of Roman forts, Iron age earthworks and the remains of stone age monuments.
English Heritage said the find was ‘really significant’ and said if they had bought a longer hosepipe, the marks may never have been spotted.
"A lot of people assume we've excavated the entire site and everything we're ever going to know about the monument is known,” said Susan Greaney, from English Heritage.
"But actually there's quite a lot we still don't know and there's quite a lot that can be discovered just through non-excavation methods.
"It's great that people who know the site really well and look at it every day were able to spot these parch marks and recognise them for what they were.
"We maintain the grass with watering when it's very dry in the summer, but our hosepipe doesn't reach to the other side of the stone circle. If we'd had a longer hosepipe we might not have been able to see them.
“It's really significant, and it shows us just how much we still have to learn about Stonehenge.”
Historians have long wondered whether Stonehenge was an intentionally-incomplete circle, but countless high resolution geophysical surveys and excavations have failed to give the answer.
Staff only water the site during the driest weeks of summer, but the hosepipe doesn't reach to the south-west quadrant where there is a gap in the circle.
Worker Tim Daw spotted the patches on the ground - now thought to be 'stone holes' - where the grass was more parched.
He said: "I was standing on the public path looking at the grass near the stones and thinking that we needed to find a longer hosepipe to get the parched patches to green up.
"A sudden light-bulb moment in my head, and I remembered that the marks were where archaeologists had looked without success for signs that there had been stone holes, and that parch marks can signify them.
"I called my colleague over and he saw them and realised their possible significance as well. Not being archaeologists we called in the professionals to evaluate them.
"I am still amazed and very pleased that simply really looking at something, that tens of thousands of people had unwittingly seen, can reveal secrets that sophisticated machinery can't."