Stonehenge secrets revealed by laser scan
Researchers using laser technology at Stonehenge have uncovered evidence which they say shows the importance of the midwinter sunset to its creators.
The scan by English Heritage showed significant differences in how various stones were shaped and worked.
It reveals that stones on the outer sarsen circle had their crust removed to make them glisten in sunlight.
This would have accentuated the view of the circle when approaching from the north-east during the solstices.
The lintels are also well worked, or "pick-dressed", compared with those that survive elsewhere in the monument.
By contrast the study has shown that the stones in the south-western segment of the circle did not have their crusts removed.
Researchers believe these variations offer proof that it was the intent of Stonehenge's builders to align the monument with the two solstices along a north-east by south-west axis, with the most dramatic view of the monument being from the Avenue, its ancient processional way which faces to the north east.
Leicester University archaeologist Clive Ruggles said: "This extraordinary new evidence not only confirms the importance of the solstitial alignment at Stonehenge, but also shows unequivocally that the formal approach was always intended to be from the north east, up the Avenue towards the direction of midwinter sunset.
"We see how the utmost care and attention was devoted to ensuring the pristine appearance of Stonehenge for those completing their final approach to the monument at the two times of the year when sunlight shines along the alignment - when those approaching had the midsummer rising sun behind or the midwinter setting sun ahead."
The laser scan and digital imaging work has also led to the discovery of 71 Bronze Age axeheads, bringing the total number of this type known in Stonehenge to 115.
English Heritage's Susan Greaney said: "We didn't expect the results of a laser scan to be so revealing about the architecture of Stonehenge and its function."
The Stonehenge laser survey was commissioned by English Heritage in 2011.
Archaeological analysis was then carried out to examine the high-resolution data that was produced for all the stone surfaces.