The mysterious circle of stones that rises on Salisbury Plain near here has stood as an archaeological marvel for thousands of years, its origins and purpose shrouded in the mists of history.
But a just-completed excavation of Stonehenge, the first within the ancient circle in more than 40 years, could provide some of the first reliable explanations for one of the greatest wonders of the prehistoric world.
A team of British archaeologists hopes to prove its theory that nearly 4,000 years ago Stonehenge was regarded not as a place of sacrament for the dead, but as a temple with healing powers.
The dig is looking closely at the 82 bluestones -- a double circle of large rocks, some weighing as much as 4 tons, that were brought in during the second stage of Stonehenge, the first stone construction at the site that began about 2150 BC.
About 150 years later, these were rearranged and encircled by much larger sarsen stones that have become iconic of Stonehenge.
Yet it is the bluestones, somehow hauled to the Salisbury Plain from the Preseli Hills in Pembrokeshire, Wales, that researchers say hold the key to the mystery.
Although the researchers found to their dismay that the area they examined had been tampered with in Roman times, they still hope the excavations will help show that the bluestones were once viewed as having therapeutic powers.
Stonehenge's legends have been many. Some have said the devil bought the stones from a woman in Ireland; another story suggests they were placed on the plain by the fabled wizard Merlin; others have claimed that aliens built the monument and left it as a place for worship, or that Druids built it as a temple for sacrificial ceremonies.
"You could put 10 archaeologists in a room and you'd get at least 11 theories," said Dr. Andrew Fitzpatrick of Wessex Archaeology, a firm involved in the excavation, which was approved by English Heritage, which manages Stonehenge.
"I think the one thing everybody would agree on is that Stonehenge is a temple, which is easy to lose sight of in the kind of to-ing and fro-ing of ideas."
But the recent realization that the site contained stones from mountains 250 miles away in Wales shed new light on Stonehenge's origins.
Tim Darvill, a professor at the University of Bournemouth, and Geoff Wainwright, president of the Society of Antiquaries of London, have spent the last six years researching Stonehenge and the rocky outcrop Carn Menyn, thought to be the site in the Preseli Hills from which the bluestones were taken.
Darvill and Wainwright, the co-directors of the dig, found the Welsh site to be a center for ceremony and burials, where the springs that flowed below the rocks were regarded by ancients as having medicinal powers.
They hope that by finding evidence to tie the stones from the Preseli Hills to those at Stonehenge, they will have an answer to the age-old question of the site's purpose.
The two men hope to establish a more precise timeline, to within 10 years, for the construction of Stonehenge by using radiocarbon dating to compare samples from the excavation with those taken from the site in Wales.
The scientists also hope to shed light on whether the stones were transported manually, as Darvill believes, or the former Irish Sea Glacier pushed them to Salisbury. But one fact is certain: Their presence makes Stonehenge unique among the stone circles of its era.
"Once they arrive here, this monument becomes very different from any other kind of monument in the British Isles. . . . And when they come here they elevate this monument into something rather special," Darvill said one recent afternoon as a student volunteer sifted dirt through a large metal sieve.
"You can make the analogy with a medieval cathedral -- it's a bog-standard Paris church until they get those relics, and at that point it becomes a beautiful, marvelous building," he said. "It changes its purpose at about that time from a fairly standard henge to a temple of really European renown."
This theory, first proposed by Darvill in a book, "Stonehenge: The Biography of a Landscape," that he wrote nearly two years ago, is in its infancy when compared with the other beliefs and cult theories about the monument that have been floated for hundreds of years. Even so, Fitzpatrick said, it is also one of the two most widely accepted current archaeological theories about the origins of Stonehenge.
The second dominant theory is being explored by Mike Parker Pearson of the University of Sheffield, who recently uncovered evidence of a village in Durrington Walls, another henge monument a few miles from Stonehenge.
Pearson believes that Stonehenge's true significance is in its relationship to a sister temple found at Durrington Walls. He believes that the two temples served as centers for religious observance -- Durrington Walls as a site of feasts for the living, Stonehenge as a series of statues of the dead.
"There is certainly a debate going on amongst archaeologists in the UK at the moment," Fitzpatrick said. "We're all kind of waiting to see how it pans out; we're waiting to see if the new excavations provide dating, which will help us resolve some of these questions."
Now that researchers have come to believe the bluestones came from Wales, the question is why. If prehistoric people believed they were ordinary rocks, surely they would not have labored to move them so far.
One clue may lie in the burial mounds that surround the site: Are they commemorations of the dead or evidence of attempts to heal the living?
"There's people in the landscape buried here who have come here perhaps like pilgrims, in order to benefit from the things here," Darvill said. "You can imagine a big temple like this is going to have shamans, it's going to have witch doctors, it's going to have all the sorts of people who in prehistoric terms would look after those who were ill."
Many of the remains uncovered during previous excavations show signs of ailments and, in some cases, primitive surgery.
"One, for example, has a trepanation taken out of the top of the skull, a circular piece of bone taken out to relieve pressure on the brain," Darvill said.
"You've got to be feeling pretty unwell to let somebody get a flint blade and cut the top of your head off."
Although the Romans may have destroyed some of the evidence that the two scientists were hoping to find, they refuse to be deterred. Their research "ties in with some big questions about the interpretation of Stonehenge," Darvill said.
"Once these bluestones were moved here, people believed the place was important, it was sacred, they could become pilgrims, they could come here." But for what?
For Darvill and Wainwright, inching closer to an answer is all they can ask for.