Archaeological investigation followed in the 20th century, with Harold St George Gray leading an excavation of the bank and ditch, and Alexander Keiller overseeing a project to reconstruct much of the monument.

The monument stands slightly above the local landscape, sitting on a low chalk ridge 160 m (520 ft) above sea level; to the east are the Marlborough Downs, an area of lowland hills.

During the Neolithic period, argillic (clayey) brownearths reigned in the landscape formed by the acidifying conditions of a closed woodland, becoming more chalky as a result of clearance and anthropogenic (human-made) interference.

[5] Pollen is poorly preserved in the chalky soils found around Avebury, so the best evidence for the state of local environment at any time in the past comes from the study of the deposition of snail shells.

[12] They compared this with similar wooden posts that had been erected in southern Britain during the Mesolithic at Stonehenge and Hambledon Hill, both of which were sites that like Avebury saw the construction of large monuments in the Neolithic.

[12] Based on anthropological studies of recent and contemporary societies, Gillings and Pollard suggest that forests, clearings, and stones were important in Neolithic culture, not only as resources but as symbols; the site of Avebury occupied a convergence of these three elements.

Between 3500 and 3300 BC, these prehistoric Britons ceased their continual expansion and cultivation of wilderness and instead focused on settling and farming the most agriculturally productive areas of the island: Orkney, eastern Scotland, Anglesey, the upper Thames, Wessex, Essex, Yorkshire and the river valleys of the Wash.[17] Late Neolithic Britons also appeared to have changed their religious beliefs, ceasing to construct the large chambered tombs that are widely thought by archaeologists to have been connected with ancestor veneration.

[21] Archaeologist Mike Parker Pearson noted that the addition of the stones to the henge occurred at a similar date to the construction of Silbury Hill and the major building projects at Stonehenge and Durrington Walls.

[citation needed] In 2017, a geophysical survey by archaeologists from the Universities of Leicester and Southampton indicated 'an apparently unique square megalithic monument within the Avebury circles' which may be one of the earliest structures on this site.

[39] Archaeologist Aubrey Burl believed that rituals would have been performed at Avebury by Neolithic peoples in order "to appease the malevolent powers of nature" that threatened their existence, such as the winter cold, death and disease.

[40] In his study of those examples found at Orkney, Colin Richards suggested that the stone and wooden circles built in Neolithic Britain might have represented the centre of the world, or axis mundi, for those who constructed them,[41] something Aaron Watson adopted as a possibility in his discussion of Avebury.

The relationships between the causewayed enclosure, Avebury stone circles, and West Kennet Long Barrow to the south, has caused some to describe the area as a "ritual complex"—a site with many monuments of interlocking religious function.

[42] Based on the scale of the site and wealth of archaeological material found in its ditches, particularly animal bone, it is theorised that the enclosure on Windmill Hill was a major, extra-regional focus for gatherings and feasting events.

[32] in 1865, the Wiltshire Archaeological and Natural History Society supported A. C. Smith and W. Cunnington to spend a week directing excavations in fourteen places, including around the Cove; they found no human bones.

Coins dating from the 1320s were found with the skeleton, and the evidence suggests that the man was fatally injured when the stone fell on him whilst he was digging the hole in which it was to be buried in a mediaeval "rite of destruction".

Archaeologist Aubrey Burl believed that the Iron Age Britons living in the region would not have known when, why or by whom the monument had been constructed, perhaps having some vague understanding that it had been built by an earlier society or considering it to be the dwelling of a supernatural entity.

It was during this Roman period that tourists came from the nearby towns of Cunetio, Durocornovium and the villas and farms around Devizes and visited Avebury and its surrounding prehistoric monuments via a newly constructed road.

[58] In the Early Middle Ages, which began in the 5th century following the collapse of Roman rule, Anglo-Saxon tribes from continental Europe migrated to southern Britain, where they may have come into conflict with the Britons already settled there.

[66] The event appears to have left a significant influence on the minds of the local villagers, for records show that in the 18th and 19th centuries there were still legends being told in the community about a man being crushed by a falling stone.

[69] In 1634, it was once more referenced, this time in Sir John Harington's notes to the Orlando Furioso opera;[69] however, further antiquarian investigation was prevented by the outbreak of the English Civil War (1642–51), which was waged between the Parliamentarians and Royalists, with one of the battles in the conflict taking place five miles away from Avebury at Roundway Down.

The two subsequently travelled to visit it together on the monarch's trip to Bath, Somerset, a fortnight later, and the site further captivated the king's interest, who commanded Aubrey to dig underneath the stones in search of any human burials.

[70] In September 1663, Aubrey began making a more systematic study of the site, producing a plan that has proved invaluable for later archaeologists, for it contained reference to many standing stones that would soon after be destroyed by locals.

In this time, he made meticulous plans of the site, considering it to be a "British Temple", and believing it to having been fashioned by the druids, the Iron Age priests of north-western Europe, in the year 1859 BC.

[75] He remarked that "this stupendous fabric, which for some thousands of years, had brav'd the continual assaults of weather, and by the nature of it, when left to itself, like the pyramids of Egypt, would have lasted as long as the globe, hath fallen a sacrifice to the wretched ignorance and avarice of a little village unluckily plac'd within it.

In the 1870s, to prevent further construction on the site, the wealthy politician and archaeologist Sir John Lubbock (later created Baron Avebury) purchased much of the available land in the monument, and encouraged other buyers to build their houses outside rather than within the henge.

[83][84] The National Trust have discouraged commercialism around the site, preventing many souvenir shops from opening up in an attempt to keep the area free from the "customary gaudiness that infiltrates most famous places" in the United Kingdom.

Meanwhile, those following the God party process around the outer bank of the henge to the southern entrance, where they are challenged as to their intent and give offerings (often of flowers, fruit, bread or mead) to the Goddess's representative.

[101] Such inaccurate ideas originated with William Stukeley in the late 17th century, who believed that Avebury had been built by the druids, priests of the Iron Age peoples of north-western Europe, who were persecuted by Roman invaders.

The Reverend R. Weaver, in his The Pagan Altar (1840) argued that both Avebury and Stonehenge were built by Phoenicians, an ancient seafaring people whom many Victorian Britons believed had first brought civilisation to the island.

[105] W. S. Blacket introduced a third idea, arguing in his Researches into the Lost Histories of America (1883) that it was Native Americans from the Appalachian Mountains who, in the ancient period crossed the Atlantic Ocean to build the great megalithic monuments of southern Britain.