New excavations near the mysterious circle at Stonehenge in southern England have uncovered dozens of homes where hundreds of people lived - at roughly the same time 4,600 years ago that the giant stone slabs were being erected.

The finding strongly suggests that the monument and the settlement nearby were a center for ceremonial activities, with Stonehenge likely a burial site while other nearby circular earthen "henges" were areas for feasts and festivals.

The houses found buried beneath the grounds of the Stonehenge World Heritage Site are the first of their kind from that late Stone Age period in Britain, suggesting a surprising level of social gathering and ceremonial behavior, in addition to impressive engineering. The excavators said their discoveries together constituted an archaeological treasure.

"This is evidence that clarifies the site's true purpose," said Michael Parker Pearson of Sheffield University, one of the main researchers. "We have found that Stonehenge itself was just half of a larger complex," one used by indigenous Britons whose beliefs centered on ancestor and sun worship.

The roughly 90 original slabs of Stonehenge, researchers have long known, were carefully placed to align with the rising and setting of the sun during the summer and winter solstices. The new research, funded in part by the National Geographic Society, concludes that a complementary and larger circle about two miles from Stonehenge had earthen-covered wooden poles aligned to mark the solstice in reverse. That monument, called Darrington Walls, was in line with sunset at the summer solstice, while Stonehenge was aligned with the sunrise on that day.

In addition, the excavation - undertaken by a team of 100 archaeologists from universities around Britain - uncovered an avenue 100 feet wide that led from the second circle down to the River Avon. That mirrors a similar, but considerably longer, wide path downstream at Stonehenge, leading the team to conclude that the two sites were connected, most likely as part of funerary rituals.

That finding, said Parker Pearson, is supported by the earlier discovery of cremated remains at Stonehenge and new work indicating that as many as 250 cremated bodies are there. It is also supported by the layout of the Darrington Walls avenue, which leads from the giant circle down to a small cliff along the river.

"My guess is that they were throwing ashes, human bones, and perhaps even whole bodies into the water, a practice seen in other river settings," Parker Pearson said. Of Stonehenge, he said: "It was our biggest cemetery of that time."

The researchers said recent carbon dating had fixed the time of Stonehenge's construction at between 2640 to 2480 B.C. with 95 percent probability - around the same time that Egyptians were constructing the giant pyramid of Giza.

See more from Stonehenge, including a photo gallery

and video, at National Geographic's Web site via EndText