Theories about Stonehenge for solstitial alignments in stonehenge and the timber circles at Durrington Walls and Woodhenge as well. Mike Parker Pearson also believes that the stonehenge was a monument of unification, bringing together different groups with different ancestries. He surmises that the five trilithons in the center of stonehenge could have symbolized five tribal lineages charting their descent from five original ancestors. The Preseli Hills might have had some ancestral significance for the stonehenge builders as well (perhaps this was their place of origin), this may have been the motive behind dragging the bluestones all the way from Preseli Hills to Wiltshire.
Stonehenge atop mounds. The mounds are known as "barrows" although they do not contain burials. Stonehenge Avenue, a parallel pair of ditches and banks leading to the River Avon, was also added. Two ditches similar to Heelstone Ditch circling the Heelstone (which was by then reduced to a single monolith) were later dug around the Station Stones. During the next major phase of activity, 30 enormous Oligocene-Miocene sarsen stones "(shown grey on the plan)" were brought to the site. They may have come from a quarry around north of Stonehenge on the Marlborough Downs, or they may have been collected from