Stonehenge: how it was built, what it was for, and every theory from Merlin to aliens

Architecture · 4 September 2026

Stonehenge was built in stages between about 3000 and 2000 BC by Neolithic farming communities of southern Britain, not by Druids, Romans or anyone from outside. The larger sarsen stones, up to 30 tons, came from the Marlborough Downs about 15 miles (25 km) north; the smaller bluestones, 2 to 5 tons, were brought some 140 miles (225 km) from quarries in the Preseli Hills of Wales, and one of them, the Altar Stone, from northeast Scotland. The monument is aligned on the midsummer sunrise and the midwinter sunset, it was the largest cremation cemetery of its age in Britain, and the people who raised the sarsens lived in a village of hundreds of houses at Durrington Walls two miles away. Below: the building sequence, the engineering, the purpose as the excavations of the last twenty years have reconstructed it, and a separate section for the theories, each with who proposed it and what the evidence says.

When and by whom

The site was in use long before the stones. Mesolithic hunters set up large timber posts nearby around 8000 BC, and a long barrow and cursus, a two-mile earthwork, were built in the fourth millennium BC. Stonehenge proper began about 3000 BC as a circular ditch and bank 360 feet (110 m) across with 56 pits, the Aubrey Holes, that held either timber posts or the first bluestones and, in and around them, cremated human remains. Around 2500 BC the great sarsen circle and the five trilithons of the horseshoe were raised; the bluestones were rearranged several times up to about 2000 BC, when building stopped. The builders were the same people who made Grooved Ware pottery and built the giant henges of Avebury and Durrington; DNA from their burials shows them to be descendants of farmers who came from Anatolia via the Mediterranean and reached Britain around 4000 BC. Stonehenge overview.

Where the stones came from

Sarsens. The 52 surviving sarsens, of about 80 originally, are a local silcrete sandstone. In 2020 a geochemical study of a core drilled from Stone 58 in 1958 matched 50 of them to West Woods near Marlborough, 15 miles north of the site. The largest trilithon upright weighs about 30 tons and stands 24 feet (7.3 m) above ground.

Bluestones. The roughly 43 smaller stones are dolerite, rhyolite and sandstone from the Preseli Hills of Pembrokeshire. Excavations at Craig Rhos-y-felin and Carn Goedog between 2011 and 2016 found the quarry faces, stone wedges and a loading platform dated to around 3400–3200 BC, earlier than Stonehenge itself, which suggests the stones stood first in a circle in Wales. A candidate for that circle, Waun Mawn, was excavated in 2021 with mixed results.

The Altar Stone. In 2024 the six-ton sandstone slab lying at the centre was shown by its mineral grains to come from the Orcadian Basin of northeast Scotland, at least 430 miles (700 km) away, probably by sea. The Altar Stone.

How it was built

• Moving. No wheel, no draught animals for heavy haulage. The sarsens were most likely dragged on wooden sledges over log rollers or greased timber tracks by teams of a few hundred people; an experiment in 2016 showed ten people could move a one-ton stone on a sledge over rails at about a mile an hour. The bluestones probably came overland along the route of the modern A40, since sea transport of the whole load would have required rafts on the open Bristol Channel.
• Shaping. The sarsens were dressed with hammerstones of harder sarsen and flint; the lintels have mortise-and-tenon joints and tongue-and-groove ends, woodworking techniques copied in stone, and their tops are curved to follow the circle.
• Raising. A pit with one sloping side; the stone slid in on its base, was tipped upright with ropes and A-frames, and packed with chalk rubble. Lintels were raised on a growing timber crib or up an earth ramp, and set onto the tenons of the uprights.
• Levelling. The tops of the sarsen circle lintels are level to within a few inches across the whole ring, although the ground slopes: the uprights were sunk to different depths.
• Labour. Estimates for the sarsen phase run to several million person-hours; that matches a population gathering seasonally from across southern Britain, and the pig bones at Durrington Walls show feasting at midwinter by people who brought animals from as far as Scotland.

What it was for

Three things are established. The sky. The axis of the monument runs from the Heel Stone through the centre to the great trilithon and points to sunrise on the summer solstice in one direction and sunset on the winter solstice in the other; the winter alignment, seen from the Avenue approaching the stones, was probably the important one, since the feasting at Durrington was at midwinter. The dead. Around 150 to 240 people were cremated and buried at Stonehenge between about 3000 and 2400 BC, the largest cemetery of its time in Britain; strontium isotopes in some of the bones show they had lived in west Wales, near the bluestone quarries. The living. The Stonehenge Riverside Project (2003–2009) led by Mike Parker Pearson found the builders' settlement at Durrington Walls, with its own timber circles and an avenue to the River Avon, and proposed that Durrington in timber was the domain of the living and Stonehenge in stone the domain of the ancestors, joined by the river. Other proposals with some support: a place of healing, based on the bluestones' later reputation, and a monument uniting the tribes of Britain by bringing stones from Wales and Scotland to one place. Durrington Walls.

Versions and theories

Everything below is a version, not a fact. These are the ideas that appear in search next to "Stonehenge theories", listed with who proposed each and what the evidence says.

Merlin and the giants

Version. Geoffrey of Monmouth wrote in about 1136 that Merlin brought the stones from Ireland, where giants had carried them from Africa, and set them up by magic. Reply. The bluestones do come from the west, which is a remarkable folk memory if it is one, but the quarries are in Wales, and the date is three thousand years before any Merlin. Geoffrey of Monmouth.

The Druids

Version. John Aubrey in the 1600s and William Stukeley in the 1700s attributed Stonehenge to the Druids, the priests of the Iron Age Celts, and modern Druid orders have held solstice ceremonies there since 1905. Reply. The Druids are first recorded by Caesar in the first century BC; Stonehenge was finished two thousand years earlier. The modern ceremonies are a tradition of their own, not a survival. Stukeley.

Romans, Danes, Phoenicians

Version. Inigo Jones in 1655 declared it a Roman temple; others proposed the Danes or Phoenician traders. Reply. Radiocarbon dating since the 1950s puts every phase in the Neolithic and Early Bronze Age, long before any of them reached Britain.

An astronomical computer

Version. Gerald Hawkins in "Stonehenge Decoded" (1965) argued the Aubrey Holes were a calculator for predicting eclipses, and Alexander Thom mapped many stone alignments. Reply. The solstice axis is real and deliberate. The eclipse machine is not: with 56 holes and hundreds of stones, alignments can be found to almost anything, and the holes held cremations, not counters. Most archaeoastronomers now accept the two solstice lines and reject the rest. Hawkins.

Ley lines and earth energies

Version. Alfred Watkins in 1921 proposed that ancient sites lie on straight "leys"; later writers turned these into lines of energy. Reply. Given the density of prehistoric sites in Wessex, straight lines through three or more of them arise by chance; no instrument has ever measured an energy at Stonehenge that is not the ordinary geology.

Glaciers moved the bluestones

Version. Some geologists have argued that an Ice Age glacier carried the bluestones from Wales to Salisbury Plain, and people only found them there. Reply. No other Welsh glacial erratics have been found on Salisbury Plain, the ice sheets are not thought to have reached that far, and the quarries in Preseli show the stones were extracted by people. The argument continues among a minority. Bluestones.

Aliens and Atlantis

Version. The usual claim that Neolithic people could not have built it. Reply. The quarries, the hammerstones, the sledge experiments, the village at Durrington with its pig bones and the cremations of the builders' own relatives leave nothing for outsiders to have done.

What is in the archive

Stonehenge is in the Ancient temples of the world collection alongside its contemporaries and elders: Newgrange in Ireland and Maeshowe in Orkney, both aligned on the winter solstice, the Maltese temples of 3600 BC, and Göbekli Tepe, six thousand years older than any of them. The pyramids of Giza, built at about the same time as the sarsen circle, are in how the pyramids were built.

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